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 chemical substance that can be utilized in the production of explosives by either mixing or blending with other substances, or by chemical processing. The vast majority of chemicals are used for legitimate purposes. However, some chemicals could potentially be misused for the illicit manufacture of homemade or improvised explosive. Indeed, relatively small amounts of select chemicals can be applied in certain processes that produce a significant amount of explosives.
material remaining from an explosive deflagration or detonation or from direct contact with an explosive. Explosive residue generally does not have a discernible morphology, can be visible or non-visible, and can contain uninitiated and post-combustion components.
Discussion—Visible explosive residue can be present in large (grams) and small (single particle or single crystal) quantities.
an arrangement of explosive components by which the initial force from the primer is transmitted and intensified until it reaches and detonates the main explosive composition.
See download
The side of a structural assembly or object that is directly exposed to the fire.
The parameter, associated with the assessment method used, that characterizes the dispersion of the values that could reasonably be attributed to the measurand.
An evaluation of practitioner performance against pre-established criteria by means of interlaboratory comparisons. [ISO/IEC 17043:2010]
the condition in which a birefringent particle appears dark when viewed between crossed polarizers.
Discussion—Most fibers exhibit extinction when their long axis is oriented parallel to the privileged direction of one of the polarizing filters.
A procedure where the reinforcement of a previously reinforced behavior is discontinued with the intention to reduce the occurrence of that behavior
To cause to cease burning.
any method of exporting data from a source.
any plot of signal intensity observed at a chosen m/z value or set of values in a series of mass spectra recorded as a function of time.
material originating from a source other than the specimen.
An estimation of a drug concentration (e.g., ethanol) at a time other than the time of sample collection. There are two types of extrpolation: back [retrograde] and forward [anterograde] extrapolation
a class of smokeless powders produced by an extrusion process where the final grain morphologies are disc or cylinder.
Organization responsible for recovering corneas/eyes from donors.
in textiles, a planar structure consisting of yarns or fibers.
in facial identification, the automated determination of the presence of human faces in digital images.
in facial identification, (1) by automated systems, the automated searching of a facial image as a probe in a facial recognition system (one-to-many), typically resulting in a group (candidate list) of facial images being returned to a human operator in ranked order based on system-evaluated similarity; (2) by humans, the mental process by which an observer identifies a person as being one they have seen before.
An investigative technique combining anatomical knowledge, artistic capability, and forensic anthropological evidence to render an estimate of an individuals facial appearance in life.
in facial identification, a manual process to identify similarities or dissimilarities between two (or more) facial images or facial image(s) and a live subject for the purpose of determining if they represent the same person or different person.
gross features considered in virtually all comparisons.
in facial identification, a formal systematic facial comparison.
the discipline of image-based comparisons of human facial features.
in facial identification, the process of collecting a biometric sample from an individual by means of a sensor.
the process of landmarking defined anthropological points.
See face recognition.
in facial identification, an adjudication of a candidate list.
A positive control (see 3.7) or negative control (see 3.6) that produces an unexpected result.
Distortion, breakage, deterioration, or other fault in an item, component, system, assembly, or structure that results in unsatisfactory performance of the function for which it was designed.
A logical, systematic examination of an item, component, assembly, or structure and its place and function within a system, conducted in order to identify and analyze the probability, causes, and consequences of potential and real failures.
A logical, systematic examination of an item, component, assembly, or structure and its place and function within a system, conducted in order to identify and analyze the probability, causes, and consequences of potential and real failures.
See drop down.
An indication/trained final response demonstrated by the canine in the absence of the target odor/scent; a situation in which the canine exhibits the trained final response in the absence of the odor/scent on which he or she was trained to find.
An indication/trained final response demonstrated by the canine in the absence of the target odor/scent; a situation in which the canine exhibits the trained final response in the absence of the odor/scent on which he /she was trained to find.
An indication/trained final response demonstrated by the canine in the absence of the target odor/scent; a situation in which the canine exhibits the trained final response in the absence of the odor/scent on which he/she was trained to find.
A depression or void that is intentionally created in a search environment by the assessor/ evaluator/handler that does not contain and has not contained the odor of human remains. This is a distractor depression or void.
Any location, person, or item incorrectly identified by the canine handler. (See false alert)
Operational usage: A response indicating that something is not true or not present when it is true or present. Scientific usage: Type II error.
Operational usage: A response indicating that something is not true or not present when it is true or present. Scientific usage: Type II error.
A response indicating that something is true or present when it is not true or absent. Scientific usage: Type I error.
A response indicating that something is true or present when it is not true or absent. Scientific usage: Type I error.
A response indicating that something is true or present when it is not true or absent. Scientific usage: Type I error.
a result that shows something is present when it really is not.
Within this document the false positive rate is defined as the number (or percentage) of Known Non-Matches which are incorrectly determined to be an Identification.
In a controlled environment, the canine responds as if a trained substance was present when it is known that it is not. (See false positive.)
Acronym for Fingerprint Acquisition12 Profile. It is a series of sets of progressivelymore stringent parameters and requirements relevant to fingerprint acquisition.[2015a>] In the Mobile ID Best Practices Recommendations Version 1, face, finger andiris application profiles were all referred to as SAP. They are referred to separately inthis standard. This was changed in Mobile ID Best Practices RecommendationsVersion 2 to be consistent with this standard. [
A European Union-funded project designed to develop an operational commonality ofidentification data between INTERPOL member countries in the event of a disaster.
a long chain alkyl group characterized by a terminal carboxyl group -COOH.
Discussion—Fatty acids are derivatized for analytical or commercial purposes, such as in an automotive fuel. A common derivatization replaces the terminal -COOH with -CO(OCH3 ), converting the fatty acid into a fatty acid methyl ester (FAME).
The Federal Bureau of Investigation of the United States Department of Justice.