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.
The fundamental unit of taxonomic classification. There is no singular species definition in biology. Essentially the term denotes a group of organisms with a unique shared evolutionary lineage.
The fundamental unit of taxonomic classification. There is no singular species definition in biology. Essentially the term denotes a group of organisms with a unique shared evolutionary lineage.
A reference to studies generally performed during developmental validation of forensic testing assays to assess if non-targeted species are detected in an assay (e.g., detection of microbial DNA in a human assay). The detection of non-targeted species does not necessarily invalidate the use of the assay, but may help define the limitations of the assay.
A reference to studies generally performed during developmental validation of forensic testing assays to assess if non-targeted species are detected in an assay (e.g., detection of microbial DNA in a human assay). The detection of non-targeted species does not necessarily invalidate the use of the assay, but may help define the limitations of the assay.
The ratio of the average molecular weight of a gas or vapor to the average molecular weight of air, or the ratio of the density of a gas to the density of dry air at standard temperature and pressure.
The ratio of the mass of a given volume of a substance to the mass of an equal volume of water at a temperature of 4C.
Ability of a method to distinguish between the targeted analyte and other non-targeted substances.
Measures the proportion of actual negatives that are correctly identified as such.
In general, studies designed to determine the ability of a procedure to discriminate between two or more substances.
Experiments performed to evaluate the ability of the system to provide reliable results for targeted analytes in the presence of cross-reactive substances.
Studies performed to assess the ability of the probabilistic genotyping system to support the absence of true non-contributors. A true non-contributor is an individual who is known not to contribute
A stated need or expectation. Specified requirements may be stated in normative documents such as regulations, standards and technical specifications.
A matrix sample collected from a specific origin for toxicological analysis. Examples include femoral or cardiac blood; left versus right eye vitreous fluid; and liver, brain, or kidney.
spectral peaks other than characteristic peaks from the sample, produced during the energy dispersive detection process. Examples include escape peaks, sum peaks, tube target coherent and incoherent scatter peaks, system peaks, and diffraction peaks.
spectral peaks other than characteristic peaks produced during the energy dispersive X-ray spectroscopy detection process; examples include escape peaks and sum peaks.
An examination of the contribution of overlap in the emission spectrum of fluorescent dyes used for a specific DNA test on a capillary electrophoresis instrument; permits the color deconvolution necessary for multi-color STR typing or sequencing to be performed; a poor spectral calibration may cause artifact peaks or inaccurate peak height determinations.
measure of the ability to distinguish between adjacent peaks in a spectrum; it is usually determined by measuring peak width at half the maximum value of the peak height or full-width half-maximum (FWHM).
Discussion—This value is usually quoted for the FWHM of Mn Kα.
measure of the ability to distinguish between adjacent peaks in a spectrum; it is usually determined by measuring peak width at half the maximum value of the peak height or full-width half-maximum (FWHM).
Discussion—Spectral resolution is not to be confused with spatial resolution (the smallest features that can be resolved in the field of view of the MSP camera or eyepieces or can be used to refer to the smallest spectral sampling area of the MSP).
measure of the ability to distinguish between adjacent peaks in a spectrum; it is usually determined by measuring peak width at half the maximum value of the peak height or full-width half-maximum (FWHM).
Audible vocalizations made with the intent of communicating information throughlinguistic content. Nonsensical vocalizations with linguistic content will be consideredas speech (including singing and chanting). Speech can be made by humans, bymachine synthesizers, or by other means.
Sphere audio data format. Information is available atftp://jaguar.ncsl.nist.gov/pub/sphere_2.6a.tar.Z
spheres composed of needles or rods all oriented perpendicular to the outer surface, or a plane section through such a sphere; a common form of polymer crystallization from melts or concentrated solutions.
shorter than course needles, but more substantial cross-section.
A training exercise in which two subjects walk the same pathway and then split into two different directions. When the canine is presented with a scent article from one of the subjects, the canine commences to trail and associate the correct person to the scent article. Despite the contamination of scent from the other person on the trail the canine is still able to discriminate between scents and identify the correct subject
A training exercise in which two subjects walk the same pathway and then split into two different directions. When the canine is presented with a scent article from one of the subjects, the canine commences to trail and associate the correct person to the scent article. Despite the contamination of scent from the other person on the trail the canine is still able to discriminate between scents and identify the correct subject.
A training exercise in which two subjects walk the same pathway and then split into two different directions. When the canine is presented with a scent article from one of the subjects, the canine commences to trail and associate the correct person to the scent article. Despite the contamination of scent from the other person on the trail the canine is still able to discriminate between scents and identify the correct subject
Loss, destruction, or material alteration of an object or document that is evidence or potential evidence in a legal proceeding by one who has the responsibility for its preservation.
the loss, destruction, or material alteration of an object or document that is evidence or potential evidence in a legal proceeding by one who has the responsibility for its preservation.
Discussion—Spoliation of evidence may occur when the movement, change or destruction of evidence, or alteration of the scene significantly impairs the opportunity of other interested parties to obtain the same evidentiary value from the evidence as did any prior investigator.
process whereby a material increases in temperature without drawing heat from its surroundings.
Discussion—Spontaneous heating is usually an exothermic oxidation reaction, which is frequently initiated by oxygen in air.
Initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material.
initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material; also known as spontaneous combustion.
The tendency of a behavior in a canine to reappear after it has undergone extinction.
in facial identification, the process by which an imposter intentionally attempts to be recognized as another person in a biometric system or intentionally attempts to be missed as an existing identity in the gallery.
a visible concentration of sample applied to the TLC plate; also known as the origin.
An analytes resistance to chemical change in a matrix under specific conditions for given time intervals
analyte’s resistance to chemical change in a matrix under specific conditions for given time intervals
a compound to prevent or slow down self-decomposition.
A location separate from the search site designated for canine handlers to wait until they are called to search.
A person or organization that can affect, be affected by, or perceive itself to be affected by a decision or activity.
An NFPA Standard, the main text of which contains only mandatory provisions using the word 'shall' to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions are not to be considered a part of the requirements of a standard and shall be located in an appendix, annex, footnote, informational note, or other means as permitted in the NFPA Manual of Style. When used in a generic sense, such as in the phrase 'standards development process' or 'standards development activities,' the term 'standards' includes all NFPA Standards, including Codes, Standards, Recommended Practices, and Guides.
An NFPA Standard, the main text of which contains only mandatory provisions using the word 'shall' to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions are not to be considered a part of the requirements of a standard and shall be located in an appendix, annex, footnote, informational note, or other means as permitted in the NFPA Manuals of Style. When used in a generic sense, such as in the phrase 'standards development process' or 'standards development activities,' the term 'standards' includes all NFPA Standards, including Codes, Standards, Recommended Practices, and Guides.
An established or widely recognized model of authority or excellence as a reference point against which other things can be evaluated or the ideal in terms of which something can be judged.
material of established origin with certified properties.
Discussion—For the purposes of fire debris analysis, this term is used for materials with a certificate of analysis from the supplier reporting the results of their characterization.
material of established origin with certified properties.