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.
Material exhibiting birefringence.
Material exhibiting birefringence.
Material exhibiting birefringence
Pre-formed or extruded pieces of soling compound that are placed in molds and pressed into the shape of a footwear outsole or heel.
The number of bits (binary digits) used to specify the brightness or color range of each pixel in an image sensor.
A continuous stream of bits transmitted over a channel with no separators between the character groups.
In computer forensics, an exact, bit-for-bit reproduction of all data objects independent of any physical media upon which that data is stored. (Compare copy.)
A low explosive composed of potassium nitrate, sulfur, and charcoal; commercial products are generally glazed and produced in specific granulation size ranges.
A commercially produced low explosive powder which is designed to replace traditional black powder in muzzle loading weapons; formulations can include potassium perchlorate in addition to potassium nitrate, or can use other fuels such as ascorbic acid. DISCUSSION: Many black powder substitutes are sulfur-free.
Thin pieces of metal in footwear and tire molds that result in molded sipes.
Broad, flat, elongated crystals.
Any area or container where target odor/scent is not present. (See blank search.)
A biological fluid or tissue (or synthetic substitute) without target analyte or internal standard
A training or certification exercise in which the target odor/scent is not present.
A training or certification exercise in which the target scent is not present.
A training or certification exercise in which the target scent is not present.
A training or certification exercise in which the target scent is not present.
A known odor/scent sample that is used to assess the canine's proficiency in a non-matching odor/scent scenario. The canine is expected to give a negative response.
The expanding leading edge of an explosion reaction that separates a major difference in pressure between normal ambient pressure ahead of the front and potentially damaging high pressure at and behind the front.
A cylindrical shell, usually of metal, containing both a primary high explosive and a secondary high explosive, which is used to initiate other explosives; also known as a detonator or cap.
Boiling liquid expanding vapor explosion.
The person(s) obtaining the measurements does not know the treatments.
A type of verification in which the subsequent examiner(s) has no knowledge of any other examiner’s decisions, conclusions or observed data used to support the conclusion.
The process of withholding information that may bias the forensic dental age assessment practitioner.
An oversized outsole made of one or more components that is later cut to size.
A panel of blood tests that measures the components of blood including electrolytes, glucose and enzymes that provides information about organ function and physiologic state.
A panel of blood tests that measures the components of blood including electrolytes, glucose and enzymes that provides information about organ function and physiologic state.
A gelatinous mass formed by a complex mechanism involving red blood cells, fibrinogen, platelets, and other clotting factors.
A deposit of blood on a surface.
A grouping or distribution of bloodstains that indicates through regular or repetitive form, order, or arrangement the manner in which the pattern was deposited.
An individual who has completed the prescribed course of study.
An injury to the skin by an object resulting in a pattern that may replicate the design of the object. (Also known as a pattern contusion.)
An estimate of the total drug in the body based on quantitative analysis of blood, urine, and/or tissue samples
Weight for frame and relative proportions of muscle and fat.
Weight for frame and relative proportions of muscle and fat.
The process of evaluating the relative fat composition of the canine. Scores are based on 1 to 5 with normal as a 2-3; or 1-9 with normal as a 4-5.
The process of evaluating the relative fat composition of the canine. Scores are based on 1 to 5 with normal as a 2 to 3; or 1 to 9 with normal as a 4 to 5.
Fluids associated with a human body (e.g., sweat, saliva, blood, vomit, decomposition fluids).
Positive relationship, rapport between canines or a human(s) and a canine.
The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.
A piece of shaped bone or other material, such as plastic or non-stick material, typically used by bookbinders to crease paper and to separate pieces of paper that are stuck together.
Checking to confirm expected outputs are obtained when inputs are at the limits of the software (e.g., testing allele frequencies below the 5/2N minimum threshold or testing upper and lower limits for amplification setup calculations).
describes the physical phenomenon of X-ray scattering from a crystallo- graphic three-dimensional lattice plane as nl=2dsinq, in which n is any integer, l is the wavelength of the X-ray, d is the crystal plane separation, also known as d-spacing, and q is the angle between the crystal plane and the diffracted beam, also known as the Bragg Angle.
the intertwining of strands in a braiding process to produce a rope structure.