Glossary
This glossary defines common preparedness terms used across Survipedia. It is written for practical use, not academic precision.
A
After-action review (AAR) : A short debrief after a drill or incident that captures what worked, what failed, and what must change next.
Anaphylaxis : A severe allergic reaction that can cause airway swelling, breathing failure, and shock. Requires immediate epinephrine and urgent care.
Aquatabs / purification tablets : Portable chemical water treatment tablets used when boiling or filtration is not available.
B
Baseline load : The minimum electrical demand you must keep running (for example: lights, communication, medical devices).
Batch cooking : Preparing multiple meals at once to reduce fuel use, labor, and daily kitchen risk during outages.
Boil order (water) : Public health instruction to disinfect tap water before drinking, usually by bringing water to a rolling boil.
Board foot : A unit of hardwood lumber volume equal to a piece 12 inches × 12 inches × 1 inch thick (30 cm × 30 cm × 25 mm). Used to price and order hardwood by volume rather than linear length.
Bow drill : A friction fire-starting method using a notched fireboard, a wooden spindle, a hand bow strung with cordage, and a hardwood handhold socket. The bow drives the spindle in rotation against the fireboard, generating fine wood dust that heats to approximately 800°F (425°C) and forms a glowing coal.
Bug-in : Staying in place during a crisis because movement is higher risk than sheltering.
Bug-out : Leaving your location due to immediate danger, with preplanned routes, staging points, and loadout limits.
C
Cistern : A dedicated container or structure for storing rainwater or other water supply, ranging from a few hundred gallons to tens of thousands of gallons. Cisterns can be above-ground (polyethylene tanks, IBC totes, galvanized steel) or below-grade (poured concrete, precast concrete, ferrocement). See Cistern systems for permanent rainwater storage.
Camp dutch oven : A flat-bottomed cast iron pot with a flanged, flat lid designed to hold hot coals on top. Unlike a kitchen dutch oven, it sits on legs and is used with coals both above and below for field baking and slow cooking without a stove.
CBRN : Chemical, biological, radiological, and nuclear hazards.
CERT : Community Emergency Response Team; local volunteer emergency training program in many regions.
Chain of custody (medical/logistics) : Documented handoff trail showing who handled a patient, medication, or critical item and when.
Charge controller : A device that regulates the flow of electricity from a solar array or wind turbine into a battery bank. Prevents overcharging and manages the charge cycle stages (bulk, absorption, float). Two types: MPPT (more efficient, required for series-wired arrays) and PWM (lower cost, small systems only).
Creosote (chimney) : A combustion byproduct that condenses on chimney flue surfaces when exhaust gases cool before exiting. Forms in three stages — dusty and flaky (Stage I), crunchy tar (Stage II), and hard glazed coating (Stage III). Stage III ignites at relatively low temperatures and can cause chimney fires reaching 2,000°F (1,093°C). Prevented by burning only dry, seasoned wood and maintaining adequate flue temperatures.
Clinker (blacksmithing) : The glassy, slag-like residue that forms as coal burns in a forge. Clinker blocks airflow through the tuyere and must be removed regularly during forging sessions.
Coke (forge fuel) : Coal that has had its volatile compounds driven off by heat, leaving a nearly pure carbon fuel. Coke burns hotter and cleaner than raw coal and is the actual fuel in the center of a working coal forge fire.
Cold soak : Process of pre-soaking dry food to reduce cooking time and fuel demand.
Comms plan : Written communication structure including roles, channels, check-in windows, and fallback methods.
Curie point (metallurgy) : The temperature at which steel loses its magnetism, roughly 1,425°F (775°C) for most carbon steels. Used as the indicator for correct hardening temperature: when a magnet no longer attracts the heated steel, the piece has reached or passed critical temperature.
D
Dado : A channel cut across the grain of a board to accept the end or edge of a mating piece. Dado joints are used for shelving, cabinet dividers, and anywhere a panel must seat in a fixed position perpendicular to a vertical member.
Defensible space : Cleared or managed area around structures to reduce wildfire spread and improve responder access.
Dehydration : Body fluid deficit that degrades performance and can progress to medical emergency.
Depth (preparedness layer) : Redundancy across multiple methods instead of reliance on one tool or one supply chain.
Drift (blacksmithing) : A tapered round or oval steel tool driven through a punched hole while hot to size, shape, and smooth the opening. Used after a punch makes a rough hole.
E
EDC (Everyday Carry) : Daily-carried items you keep on your person for immediate use.
Egress : A safe route to exit a structure or area.
EMP : Electromagnetic pulse that can damage vulnerable electronics and infrastructure.
F
Fallback : Predefined backup action if the primary plan fails.
Fatwood : The resin-saturated heartwood from the base of old pine trees or stumps. The resin content makes fatwood ignite readily from a ferro rod and burn hot even in damp conditions. It is shaved into fine curls with a knife for use as fire-starting tinder.
Ferro rod : A fire-starting tool made from a pyrophoric alloy (typically cerium-based ferrocerium) that produces a shower of sparks at roughly 6,000°F (3,315°C) when a striker is scraped along its surface. Works when wet, does not run out of fuel, and requires no heat to operate.
Field-expedient : A practical improvised method used when ideal tools are unavailable.
Fireboard (bow drill) : The flat piece of dry softwood (willow, cottonwood, basswood, cedar) in a bow drill fire-starting set. The spinning spindle drills into a notched socket in the fireboard, generating fine wood dust that accumulates in the notch and ignites into a coal.
Ferrocement : A construction technique using cement-rich mortar applied over a wire mesh armature, without formwork or rebar cages. Used for boats, water tanks, and cisterns since the 1840s. A ferrocement cistern requires no specialized formwork, uses less cement than a poured tank of the same volume, and can be built by a skilled owner-builder into any shape. Wall thickness is typically 3/4–1 inch (1.9–2.5 cm).
First-flush diverter : A passive device installed on a downspout that discards the first volume of runoff from a rain event — which carries the heaviest concentration of roof contaminants — before routing cleaner water to cistern storage. A small drain hole in the bottom of the chamber empties it slowly between rain events (target: 24–48 hours). Standard sizing is 12.5 gallons per 1,000 square feet (0.52 L per sq m) of roof area served.
First-in, first-out (FIFO) : Rotation method where oldest supplies are used first to prevent spoilage and waste.
G
Greywater : Relatively low-contamination wastewater (for example from sinks/showers) that may be reused for non-potable purposes if managed correctly.
Grid down : Extended electrical outage affecting normal utility-dependent systems.
HDPE #2 (High-Density Polyethylene) : A rigid plastic resin identified by the recycling symbol with "2" inside it. HDPE #2 does not leach chemicals into water under normal storage conditions and is the standard material for food-grade water storage containers. A container must be both HDPE #2 and certified food-grade — the two designations are not interchangeable.
Hackling : The final fiber-preparation step in processing flax or nettle for spinning. Fiber bundles are drawn through a hackle — a board set with metal tines — to align the long line fibers parallel and separate them from the shorter tow fibers. The result is a smooth, parallel fiber supply ready for the drop spindle.
HELP position : Heat Escape Lessening Posture. A cold water survival position in which the arms are crossed tightly over the chest and knees are drawn toward the chest. Developed by Dr. John Hayward, laboratory testing showed HELP reduces the rate of core temperature cooling by approximately 69% compared to passive floating.
H
Hardening : Physical upgrades that make a system or location more resistant to failure or attack.
Hardy hole (blacksmithing) : The square socket in an anvil, typically 1 inch (25 mm) across, that accepts hardy tools such as a hardy cut, bottom swage, or bick. Tools that fit the hardy hole are held securely by the anvil while work is driven onto them from above.
Heat index : Combined temperature and humidity metric indicating apparent heat stress on the body.
Hypothermia : Dangerous drop in core body temperature causing cognitive and physical impairment.
I
IBC tote (Intermediate Bulk Container) : A reusable industrial-grade container typically holding 275–330 gallons (1,040–1,249 L). New food-grade IBC totes use virgin HDPE certified to NSF/ANSI Standard 61 for drinking water contact. Used totes are available at lower cost but must be verified to have held only food-grade contents — totes that previously held industrial chemicals or solvents cannot be decontaminated for drinking water use.
IFAK : Individual First Aid Kit, typically focused on major trauma control.
Incident command : Structured way to assign authority, roles, and communication during emergencies.
K
Kerf : The slot or channel left by a saw blade as it cuts through wood. Kerf width depends on the blade's tooth set — typically about ⅛ inch (3 mm) for a standard hand saw. When calculating cut-list lengths, always subtract kerf width from the waste side, not the finished piece.
L
Ludwig's angina : A rapidly progressing bacterial cellulitis of the floor of the mouth and submandibular space. It is not a dental problem — it is an airway emergency. Swelling can close the airway within hours. Warning signs include swelling under the chin or into the neck, difficulty swallowing, drooling, stridor, trismus (inability to open the mouth fully), and high fever. Requires emergency hospital care, IV antibiotics, and possible surgical drainage. Approximately 8% of untreated cases are fatal.
LiFePO4 (lithium iron phosphate) : A lithium battery chemistry with 2,500–6,000 discharge cycles to 80% capacity, thermal runaway threshold of 270–300°C (518–572°F), and the ability to discharge to 90% depth without damage. The preferred chemistry for off-grid battery banks and portable power stations due to its safety, longevity, and tolerance for partial states of charge during storage.
Load shedding : Intentionally turning off non-critical electrical loads to preserve power for priority systems.
Lumen : Total visible light output from a lamp or flashlight.
MPPT (Maximum Power Point Tracking) : A charge controller algorithm that continuously adjusts the operating voltage of a solar array to extract maximum power output, then steps the voltage down to match the battery bank. MPPT controllers recover 20–30% more energy than PWM controllers, particularly in cold weather and when panel strings are wired in series at voltages above battery voltage.
Magnetic declination : The angular difference between True North (the geographic pole that maps are drawn toward) and Magnetic North (where a compass needle points). Declination varies by location — it ranges roughly from 20° west in the Pacific Northwest to 15° east in Maine across the contiguous United States. Always apply the correct declination when using a compass with a topographic map.
Micarta : A composite handle material made from layers of natural cloth (canvas, linen, or paper) impregnated with phenolic resin and compressed under heat. It provides excellent grip that improves when wet. A common material for field knife handles where wet-weather performance is a priority.
M
Martensite : The hard, brittle crystal structure that forms in high-carbon steel when it is rapidly quenched from above its critical temperature. Hardened steel is essentially martensite; tempering converts some martensite to tougher phases to reduce brittleness.
Mortise-and-tenon : A structural wood joint where a projecting rectangular tab (the tenon) on one piece fits into a matching cavity (the mortise) in the other. When glued, the joint is stronger than either piece of wood individually. Used in furniture frames, door frames, and timber framing.
Mass casualty incident (MCI) : Event where patient count exceeds immediate treatment capacity.
Mutual aid : Reciprocal support agreements between neighbors, groups, or jurisdictions.
Mylar bag (food storage) : A multi-layer laminated foil bag made from biaxially oriented polyethylene terephthalate (BOPET). Used in food storage because it blocks oxygen, moisture, light, and odors. When heat-sealed and paired with an oxygen absorber, a Mylar bag inside a food-grade bucket can preserve dry staples (grains, legumes, sugar, salt) for 10–30 years.
N
NMC (nickel manganese cobalt) : A lithium battery chemistry found in many entry-level portable power stations and EV battery packs. Offers 500–800 cycles to 80% capacity and a thermal runaway threshold of 150–210°C (302–410°F). Lower upfront cost than LiFePO4 but higher long-run cost per cycle and less tolerant of heat and prolonged partial charging.
N+1 redundancy : Reliability pattern where one additional backup unit exists beyond minimum required capacity.
NVD / NVG : Night vision device / night vision goggles for low-light observation.
O
Off-gassing : Release of chemicals or fumes from materials, fuels, or containers.
Oxygen absorber : A small sachet containing iron powder and salt that reacts with oxygen inside a sealed container, reducing the headspace oxygen level to below 0.01%. Used in Mylar bags and #10 cans to prevent oxidation, insect hatching, and aerobic microbial growth in dry bulk food storage. Sized in cubic centimeters (cc); a 2,000–2,500 cc absorber handles a 5-gallon (18.9 L) Mylar bag of grain or legumes.
OPSEC : Operational security; reducing exposure of sensitive information that could be exploited.
ORS (oral rehydration solution) : Balanced fluid/salt/sugar mixture used to treat dehydration.
P
Peak sun hours (PSH) : A measure of solar energy availability. One peak sun hour equals 1,000 watts per square meter (W/m²) of solar irradiance received over one hour. It is not the same as hours of daylight — a partly cloudy 10-hour day may yield only 3–4 PSH. Used to estimate daily solar panel output: array watts × PSH = daily watt-hours produced.
Penstock : The pressurized pipe that carries water from the intake of a micro-hydro system down to the turbine. Typically made from HDPE pipe for heads under 75 m (246 ft). Designed for flow velocity of 2.5–3.5 m/s (8–11.5 ft/s) to balance friction losses against pipe cost.
PPE : Personal protective equipment such as gloves, eye protection, respirators, and hearing protection.
Pressure canning : High-temperature canning method required for low-acid foods.
Punk wood : The dry, powdery, fibrous interior of a partially rotted hardwood log. Good punk wood crumbles to dust when pinched and smolders for an extended period after receiving a spark, making it ideal for transferring a friction-fire coal to a tinder bundle.
Primary / secondary / tertiary plan : Layered priority sequence of methods so operations continue when one method fails.
Parulis : A raised, pimple-like swelling on the gum surface that forms when an abscess finds a drainage path through the bone and gum tissue. Also called a gum boil. The appearance of a parulis means the abscess is draining — it reduces pain pressure but does not resolve the underlying infection.
Periodontal ligament (PDL) : The network of fibrous connective tissue fibers that anchor a tooth root to the surrounding bone socket. PDL cells are responsible for the reattachment of a reimplanted tooth after avulsion. They begin dying within minutes of air exposure and cannot survive in plain tap water — storage in cold milk or saline is required to maintain viability during transport.
Pritchel hole (blacksmithing) : The round hole near the hardy hole in an anvil face. During punching operations, the work is repositioned over the pritchel hole so the punch slug can fall through without damaging the anvil.
Q
Quarantine : Restricting movement of exposed individuals to reduce disease spread during incubation windows.
Retting : A controlled rotting process that uses moisture and microbial action to dissolve the pectin binding plant fibers (flax, nettle) to the woody core of the stalk. Dew retting spreads stalks on grass for 2–4 weeks; water retting submerges them for 4–7 days. Retting is the first step in processing plant fiber for spinning.
R
Rabbet : A step-shaped cut along the end or edge of a board, leaving a recessed lip that overlaps a mating piece. Stronger than a butt joint because the shoulder carries shear load and the glue surface is long-grain. Common in cabinet backs, drawer bottoms, and box corners.
Rationing : Controlled allocation of finite resources to extend operational duration.
Resilience : Capacity to absorb disruption, adapt, and continue core function.
Risk threshold : Predetermined trigger point where action escalates (evacuate, shelter, call aid, etc.).
Scandi grind : A blade grind geometry where a single flat bevel runs from the spine to the cutting edge, with no secondary micro-bevel. The flat bevel registers precisely against wood for carving and sharpens easily because the entire bevel lies flat on the stone. Common on Scandinavian bushcraft knives.
Selvage : The finished edge of handwoven cloth at the left and right sides of the loom, where the weft thread turns back on itself. Maintaining even selvage tension is the primary skill challenge in learning to weave — too much tension causes draw-in, narrowing the cloth.
SHGC (Solar Heat Gain Coefficient) : The fraction of solar radiation that passes through a window as heat. Ranges from 0 to 1; higher values admit more solar heat. Passive solar south-facing windows in cold climates require SHGC 0.50 or higher. North, east, and west windows in hot climates benefit from SHGC 0.25 or lower to reduce cooling load.
SMAW (Stick welding) : Shielded Metal Arc Welding. A welding process that uses a flux-coated consumable electrode (welding rod) as both the filler metal and the shielding source. The flux coating vaporizes during welding to protect the molten pool from atmospheric contamination, eliminating the need for a separate shielding gas cylinder. The most practical welding process for off-grid and field repair.
S
STC (Standard Test Conditions) : The laboratory benchmark used to rate solar panel output: 1,000 W/m² irradiance, 25°C (77°F) cell temperature, and 1.5 air mass spectrum. Real-world panel output is typically 10–20% lower than the STC nameplate rating due to higher cell temperatures in field conditions.
SIP (shelter in place) : Staying indoors and controlling exposure when external conditions are unsafe.
Situational awareness : Continuous understanding of environment, threats, and options for action.
SOP (standard operating procedure) : Written, repeatable process for critical tasks.
Stress inoculation (training) : Controlled exposure to pressure during practice to improve real-event performance.
T
THD (Total Harmonic Distortion) : A measure of power quality expressed as a percentage. Standard utility AC power has THD below 5%. Pure sine wave inverters produce THD below 3%, safe for all electronics. Modified sine wave inverters produce THD of 25–45%, which can damage motors, CPAP machines, variable-speed drives, and sensitive electronics.
Toenailing : A carpentry fastening technique where nails are driven at opposing angles (typically 45–60 degrees) through the end grain of one board into the face of a mating piece. Used when face-nailing straight through is not possible, such as attaching studs to a sill plate.
TPI (teeth per inch) : A measure of saw blade tooth density. Lower TPI (4–6) removes material quickly and is used for ripping along the grain. Higher TPI (8–12) produces smoother cross-cuts. Japanese pull saws often specify TPI as the equivalent of their metric tooth spacing.
Tinder bundle : A layered nest of dry combustible material used to catch a spark or glowing coal and nurse it into an open flame. Properly constructed in three grades: coarse outer layer (bark strips, dead leaves), medium middle layer (shredded inner bark, dry grass), and fine inner core (cattail fluff, punk wood dust, scraped birch shavings).
Triage : Prioritizing treatment by severity and survivability when resources are limited.
Thermal imaging : Detection of heat signatures to identify people, animals, and hotspots in low visibility.
Throughput (operations) : Rate at which a team can process tasks or people over time.
Tuyere (blacksmithing) : The air inlet pipe beneath a coal forge fire pot through which a blower forces air into the fire zone. Pronounced "twee-air." Clinker accumulating over the tuyere restricts airflow and drops forge temperature.
UTM (Universal Transverse Mercator) : A metric coordinate grid system that divides the world into numbered zones. Positions are given as meters east (easting) and meters north (northing) within a zone, making distance calculations straightforward: 1,000 added to the northing value equals 1,000 m (0.62 miles) north on the ground. USGS 7.5-minute topographic maps print UTM grid lines in the margins.
U
UV disinfection : Water treatment using ultraviolet light to inactivate many pathogens.
V
Vertical evacuation : Moving to higher floors or elevated structures when horizontal escape is blocked (for example tsunami zones).
W
Water-bath canning : Boiling-water canning method for high-acid foods only.
Watt-hour (Wh) : Unit of stored or consumed energy over time.
Wet-bulb temperature : Heat stress indicator combining temperature and humidity; high values can prevent effective body cooling.
X
X-band weather radar (consumer context) : Short-range radar references often used in weather monitoring systems; performance depends heavily on placement and clutter.
Z
Zone defense : Security model where areas are monitored and controlled by predefined sectors and response responsibilities.
If a term is missing or used differently across regions, submit an update request through feedback.