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 presence of more than one mitochondrial DNA (mtDNA) sequence or type within a single individual.
The presence of more than one mitochondrial DNA (mtDNA) sequence or type within a single individual.
The presence of more than one mitochondrial DNA (mtDNA) sequence of type within a single individual.
The presence of more than one mitochondrial DNA sequence or type within a single individual.
In computer forensics, a sector in the current configuration of a drive that cannot be accessed by read and write commands without changing the drive configuration.
Discussion—Sectors in a host protected area would be hidden data sectors.
A material that is capable of sustaining a reaction front that moves through the unreacted material at a speed equal to or greater than that of sound in that medium [typically 1000 m/sec (3000 ft/sec)]; a material capable of sustaining a detonation. (See also detonation.)
energetic materials that support a supersonic detonation wave, irrespective of the ambient condition of confinement; sometimes abbreviated HE.
descriptive of an explosive that undergoes complete reaction (or detonation) of the material as designed.
An impression with observed data that are unambiguous and self-evident due to high clarity and quantity.
In this document, it refers to a MS instrument that can give at least 10,000 nominal mass resolving power at full width of the peak at half its maximum height (FWHM) for the compound of interest.
A rapid pressure rise or high-force explosion characterized by a shattering effect on the confining structure or container and long missile distances.
An abnormal formation of the hip socket.
a graph of a frequency distribution in which rectangles with bases on the horizontal axis are given widths equal to the class intervals and heights equal to the corresponding frequencies.
Discussion—In digital images, a histogram is frequently used to document the number of pixels of a given brightness value (for example, 0-255).
Cellular level assessment of skeletal and dental materials.
A calibration that was performed and stored prior to the preparation and/or analysis of the case samples and quality control samples
Sequence(s) returned from GenBank® when performing a BLAST search. Also known as a “subject sequence.”
Homemade Explosives.
a 'dummy' device designed to appear as a bomb, but missing explosive or other components such that the device would not function as a bomb.
in facial identification, a process of comparing faces by looking at the face as a whole and not the component parts in isolation.
often abbreviated as HME; any explosive not commercially manufactured; also known as improvised explosives.
Death as a result of a volitional act or act of omission (e.g., injury, poisoning, gross neglect of a child) committed by another person to cause fear, harm, pain, or death. Intent to cause death is a common element but is not required for use of the manner of homicide. The classification of homicide for the purposes of death certification is a "neutral" term and neither indicates nor implies criminal intent, which remains a determination within the province of legal processes.
NOTE There may be cases, such as acts of serious neglect (e.g., firing a bullet into the air) or application of force (e.g., restraint) that, in the opinion of the certifier, warrant the classification of homicide..
a series of organic compounds in which each successive member has one more repeating unit (for example, methylene group, -CH2-) in its molecule than the nearest preceding member.
Discussion—For example, methanol, ethanol, propanol, etc., form a homologous series as do nonane, decane and undecane, etc.
A region of DNA made up of a single repeated base.
A segment of DNA consisting of repeats of a single nucleotide; may cause slippage during amplification and sequencing.
Autopsy requested by a medical caretaker or healthcare facility, usually authorized by the next of kin.
in facial identification, a bright area of light reflecting on a face that reduces the visibility of features.
A base or region of DNA that mutates more frequently than areas around it.
hue is that attribute of a color in the Munsell color system by which we distinguish red from green, blue from yellow, etc.
Discussion—The Munsell color system has principal hues of red (R), yellow (Y), green (G), blue (B), and purple (P), placed at equal intervals around a neutral point. Between the principal hues are five intermediate hues: yellow-red (YR), green-yellow (GY), blue-green (BG), purple-blue (PB) and red-purple (RP). Munsell hue is designated with an alpha-numeric code (for example, 7.5YR).
Non-target person placed within a search area.
Non-target person placed within a search area.
Non-target person placed within a search area.
Non-target person placed within a search area.
The analysis of specimens for driving while impaired cases, drug-facilitated crimes, and other impairment cases (e.g., child custody).
The way in which human scent moves or reacts in a given environment. Factors that influence the dispersion of scent may include wind, temperature, air currents, and topography. An example would be a plume of scent that a canine has been trained to follow to its target.
A particular person's scent collected for use for investigative purposes.
A particular persons scented article collected for use for investigative purposes.
A particular persons scented article collected for use for investigative purposes.
A particular persons scented article collected for use for investigative purposes.
A canine trained to locate and indicate items in question by means of detecting human scent.
Individual that laid a track/trail for a canine to follow to the exclusion of all other trails
Individual that laid a track/trail for a canine to follow to the exclusion of all other trails.
Individual that laid a track/trail for a canine to follow to the exclusion of all other trails.
Search determinedly for someone or something
Search determinedly for someone or something.
The innate impulse of a canine to search determinedly using the senses of smell, sight, hearing, and/or taste.
The science of providing for the needs of an animal including housing, daily care, feeding, exercise, and meeting the behavioral/mental/emotional needs of the animal.
The science of providing for the needs of an animal including housing, daily care, feeding, exercise, and meeting the behavioral/mental/emotional needs of the animal.
An explosible heterogeneous mixture, comprising gas with suspended solid or liquid particulates, in which the total flammable gas concentration is 10 percent of the lower flammable limit (LFL) and the total suspended particulate concentration is 10 percent of the minimum explosible concentration (MEC). [68, 2018]