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.
Lowest number of points, including a chromatographic separation, that must be achieved within a testing regimen to identify an analyte in a specific matrix.
The lowest capacitive spark energy capable of igniting the most ignition-sensitive concentration of a flammable vapor-air mixture or a combustible dust-air mixture as determined by a standard test procedure. [652, 2019]
A minimum estimate of the number of individuals represented by a sample; calculated as the number of the most repeated element after sorting by element, side, and developmental status.
Written documents established to define the least level of performance considered acceptable.
The point where a friction ridge terminates, or splits into two or more ridges. A subset of the friction ridge detail/features traditionally consisting of ridge endings, bifurcations, and dots used to compare and interpret similarity and dissimilarity between two impressions.
The point where a friction ridge terminates, or splits into two or more ridges. A subset of the friction ridge detail/features traditionally consisting of ridge endings, bifurcations, and dots used to compare and interpret similarity and dissimilarity between two impressions.
The point where a friction ridge begins, terminates, or splits into two or more ridges.Minutiae are friction ridge characteristics that are used to individualize a friction ridgeimage (fingerprint, palm print, plantar). This is also known as Level 2 detail.
The point where a friction ridge terminates, or splits into two or more ridges. A subset of the friction ridge detail/features traditionally consisting of ridge endings, bifurcations, and dots, or any combination thereof, used to compare and interpret similarity and dissimilarity between two impressions.
When the canine fails to alert in the known presence of the target odor/scent.
Performance demanded of a person or canine team in accordance with certain fixed regulations, needs of the department or agency. Compulsory pre-requisites needed before deployment.
Performance demanded of a person or canine team in accordance with certain fixed regulations, needs of the department or agency. Compulsory pre-requisites needed before deployment.
Performance demanded of a person or canine team in accordance with certain fixed regulations, needs of the department or agency. Compulsory pre-requisites needed before deployment.
Small circular DNA molecules located in structures used to provide energy to the cell(mitochondria). Their small size and abundant nature make them particularly useful whenexamining small or much damaged biological material. It can be used to trace maternallineages as it is only inherited from ones mother.
An often small (~16,500 bp in humans), circular DNA molecule located in eukaryotic mitochondria that is typically maternally inherited; the resistance to degradation and presence of multiple copies of mtDNA in each cell make it useful with samples originating from limited or damaged biological material.
A small, circular DNA molecule located in eukaryotic mitochondria that is typically maternally inherited; the resistance to degradation and presence of multiple copies of mtDNA in each cell makes it useful with samples originating from limited or damaged biological material.
A small (~16,500 base pairs), circular DNA molecule located in eukaryotic mitochondria that is typically maternally inherited; the resistance to degradation and presence of multiple copies of mtDNA in each cell makes it useful with samples originating from limited or damaged biological material; 2 variations in the DNA sequence may be used for distinguishing individuals, and in biological relationship and ancestry testing
Any biological sample containing DNA from more than one individual
Any biological sample containing DNA from more than one individual.
DNA typing results originating from two or more individuals.
Experiments performed to evaluate the performance of the test method when samples containing mixtures of similar or different body fluids and/or cell types are assayed.
a portable device that has an embedded system architecture, processing capability, on-board memory, and may have telephony capabilities (for example, cell phones, tablets, and smartphones).
the moving liquid phase used for development.
for legal purposes, the utilization of scientific methodologies to recover data stored by a cellular device.
Samples of known origin that mimic or simulate a range of casework sample types that may include laboratory created samples or proficiency test samples.
This is a type or class of biometric system. Any measurable biological or behavioralcharacteristic can be a biometric modality.
a geometrical parameter used in the characterization of noncircular fiber cross-sections.
Discussion—The modification ratio is the ratio in size between the outside diameter of the fiber and the diameter of the core; it can also be called “aspect ratio.”
Ion formed by the removal of one or more electrons from a molecule to form a positive ion or the addition of one or more electrons to a molecule to form a negative ion.
a breakable container filled with an ignitable liquid. It can be ignited by a flaming wick or by chemical means.
a breakable container filled with an ignitable liquid. It can be ignited by a flaming wick or by chemical means.
a hair disorder that results in periodic nodes or beading along the length of the hair with intervening, tapering constrictions that are not medullated.
a hair disorder that results in periodic nodes or beading along the length of the hair with intervening, tapering constrictions that are not medullated.
an oriented polypropylene film in which the polymer has been stretched in only one direction during the manufacturing process. Tapes with such films can be torn by hand.
device designed to isolate narrow wavelength ranges of light from complex, broad-spectrum radiation.
Relating to a branch of biology that deals with the form of living organisms, and with relationships between their structures.
in facial identification, direct comparison of class and individual facial characteristics without explicit measurement.
Conformance with the form and structure of the internal content, and verification that thedata structures exist and have correct values.
An estimation based on qualitative phenotypic traits without explicit measurement.
Assignment of tooth numbers based upon the shape of the teeth. This is in contrast topositional tooth numbering, which assigns a tooth number based solely upon position,and does not consied the shape of the tooth. For most cases, the tooth numberassignment would be the same. Differences arise only in unusual cases.
referring to size, shape, structure, and texture.
Quantitative data that incorporates both size and shape.
Quantification technique to estimate the actual number of individuals based on the number of paired and unpaired bones; a modified Lincoln Index (LI).
Mindset and physical behaviors associated with interest, willingness, and keenness to work.
The degree to which an animal is inclined to perform a goal-directed behavior based on internal and external stimuli.
segregations within the soil matrix with different color or shades of color interspersed with the dominant (matrix) color.
Discussion—The NCSS reserves the term mottles for color variations that cannot be associated with compositional properties of the soil, whereas color variations attributable to compositional variations are designated with distinct terms (redoximorphic features, concentrations, ped coatings, etc.). However, in a forensic examination mottling is often used to describe any color contrast within a soil aggregate, regardless of its origin.
An encoding format commonly used for audio recordings. It is also called MPEG-1 orMPEG-2 Audio Layer III. It has used the file extension '.mp3' since 1995.