OSAC Lexicon
The OSAC Lexicon is a compendium of forensic science terms and definitions. This terminology tool was created to help bring consistency and understanding to the way terms are used by the various forensic science. Use of the OSAC Lexicon does not replace the need to reference the original published source.
The terms and definitions in the OSAC Lexicon come from the published literature, including documentary standards and technical reports. It is continually updated with the latest work from OSAC units, as well as terms from newly published documentary standards and standards elevated to the OSAC Registry.
Gradually terms are evaluated and harmonized by the OSAC to a single term. This process results in an OSAC Preferred Term. An OSAC Preferred Term is a term, along with its definition, that has undergone review and evaluation by the FSSB Terminology Task Group and has been approved by the FSSB. The FSSB recommends that subcommittees use OSAC Preferred Terms when drafting standards.
The OSAC Lexicon should be the primary resource for terminology and used when drafting and editing forensic science standards and other OSAC work products.
A regularly irregular heart rhythm associated with changes in breathing, normal finding in the canine.
The general physical location of the incident, including the scene and the surrounding area deemed significant to the process of the investigation and support areas.
Osseous, cartilaginous, and/or dental tissues.
a crystal in which all of the spaces in the crystal lattice are not occupied.
Osseous, cartilaginous, and dental tissues.
A defect to osseous, dental, and/or cartilaginous tissue as a result of external forces.
Osseous, cartilaginous, and/or dental tissues.
Osseous, cartilaginous, and/or dental tissues.
A representation of a friction skin image in which all pixels are white except for a 1-pixel-wide thinned black skeleton following the midpoint of each ridge. Also known as aridge tracing.
a magnetic card reader, specifically when used for an illegal purpose.
using a skimmer to acquire PII in an unauthorized manner.
A technique involving the superimposition of a facial photograph or video of a known individual with an unidentified skull.
The accidental discharge of a firearm upon closing of the action.
Slap fingerprints (slaps) are taken by simultaneously pressing the fingers of one hand(i.e., without the thumb) onto a scanner or fingerprint card. Slaps are also known as fourfinger simultaneous plain impressions (although if the person has more than four fingerson a hand, all of the fingers may be included in the slap image).
thickened liquid solution of oxidizers and fuels blended with additional solid oxidizers and fuels with sensitizers.
Discussion—The main oxidizer is ammonium nitrate. Slurry explosives are more liquid-like than water gel explosives.
a transfer of paint resulting from contact between two objects; these transfers can consist of co-mingled particles from two or more sources, fragments, or contributions from a single source.
The airborne solid and liquid particulates and gases evolved when a material undergoes pyrolysis or combustion, together with the quantity of air that is entrained or otherwise mixed into the mass.
The condensed residue of suspended vapors and liquid products of incomplete combustion.
See backdraft.
A discoloration resulting from deposits of the solid constituents in smoke.
a propellant and low explosive composed of nitrocellulose and other organic and inorganic compounds
an explosive designed to deflagrate with minimal smoke production and used in ammunition as a propellant; can be single, double, or triple base.
Discussion—Some smokeless powders can detonate with proper initiation.
Combustion without flame, usually with incandescence and smoke.
Scar, (needle) mark, and tattoo information.
A protective device to permit dry firing without damage to the firing pin.
Extraction of an audio signal from an original recording in a way that disrupts thecontinuity and time record of the original recording.
Aerosol waxes used to coat the surface of snow impressions prior to casting.
An accelerated plaster that is applied in a prescribed way and is capable of casting all forms of snowimpressions.
The period of behavioral maturation that appears to be correlated, in species in which it has been studied, with changes in brain chemistry. Canines' temperaments can be considered relatively stable after this period, although learning continues. The broad range cited for social maturity is 12 to 36 months, and the narrow range cited is 18 to 24 months.
The exposure of canines to other canines, humans, and animals of different species during the sensitive period when they are best able to begin to learn about such stimuli.
The legal entity or vendor company which created and/or provides a software program.
Confirmation, through the provision of objective evidence, derived from a series of documented tests, of the compliance of a software system with intended use and applicable guidelines.
Part of a software program. Programs are typically composed of one or more independently developed modules. Modules may be acquired as additions to a software program already in use, or they may be fully integrated into the software program (e.g., add-ins/plug-ins, and macros).
A set of instructions, modules or procedures, that allow for a certain type of computer operation. Interchangeable terms include software application and software product.
Individual trial designed to evaluate specific software functions.
Different categories of trials that comprise the software internal validation.
sediments or other unconsolidated accumulations of solid particles (for example, minerals and organic matter) that are produced by the physical, chemical, and biological disintegration of parent material, or which has the ability to support rooted plants in a natural environment, or both; and which can include manufactured materials.
Discussion—Within this document, "soil" includes native soil, as well as unconsolidated material emplaced by human activities.
a device used to collect virtually undisturbed sub-surface soil samples for documenting a soil profile.
a layer of soil or soil material approximately parallel to the land surface and differing from adjacent genetically related layers in physical, chemical, and biological properties or characteristics such as color, structure, texture, consistency, kinds and numbers of organisms present, degree of acidity or alkalinity, etc.
a vertical section of soil exposed from the ground surface to a depth of interest. A soil profile can be observed in a freshly dug pit, along a road bank, or in many other places.
A method of isolating DNA from cells involving selective absorption to small silica or other particles/membranes, removal of non-DNA materials by washing, and release of DNA from the particles/membranes for analysis.
an extraction technique where the analytes from a sample are adsorbed onto a fiber coated with an adsorptive medium and thermally desorbed into the injection port of a gas chromatograph.
in TLC, a mixture of components to be separated.