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.
Property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty
property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of comparisons, each contributing to the measurement uncertainty (see 2.4.1 of International Vocabulary of Metrology (VIM) Basic and General Concepts and Associated Terms [10]).
Military Grid Reference System
a chart relating thickness, birefringence, and retardation so that any one of these variables can be determined when the other two are known.
the decomposition of petroleum products in fire debris by bacterial action that can diminish some compounds, resulting in an altered pattern in a chromatogram.
An implant that is placed under the skin of an animal that provides a unique electronic identification.
An implant that is placed under the skin of an animal that provides a unique electronic identification.
a small drop of liquid that would fit on the end of a standard size, flattened toothpick; the approximate volume of this drop would be 10 to 25 µL.
a term that describes characteristics too small to be resolved by the unaided eye, but large enough to be resolved with a microscope.
concerning a microscope or the use of a microscope.
A specialized spectrophotometer designed to measure the absorbance, reflectance and emission spectra of microscopic areas on samples.
sample preparation approach that sequentially passes a blade at a shallow depth through a sample resulting in sections of selected thickness as well as a flat block.
a sample preparation method that sequentially passes a blade at a shallow depth through a specimen, resulting in sections of selected thickness.
pertaining to the IR region of the electromagnetic spectrum with wavelength range from approximately 2.5 to 25 µm (wavenumber range approximately 4000 to 400 cm-1).
the movement over a period of time of an ingredient from one layer to another.
Discussion—This often occurs in electrical tapes where plasticizer in the polyvinyl chloride (PVC) backing "migrates" into the adhesive.
Minute (of time)
a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form(s), and physical properties, or an element or chemical compound that is crystalline and that has formed as a result of geological or pedogenic (soil-formed) processes.
Discussion—Artificial and biogenic crystalline materials are not minerals but can occur in geological materials (for example, cement powder, lime, lye, biogenic calcite, biogenic hydroxyapatite, bricks) and can be detected by XRD.
The minimum concentration of a combustible dust cloud that is capable of propagating a deflagration through a uniform mixture of the dust and air under the specified conditions of test. [68, 2018]
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, or any combination thereof, 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 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.
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.
Organelles found in eukaryotes (including humans) that provide the energy for the cell; contains DNA inherited from an individual’s biological mother.
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.”