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 size, strength, or duration of a reward following a behavior.
the final explosive in an explosive train.
Continuing training conducted beyond the initial training of a discipline, designed to maintain a level of proficiency by ensuring the canine team's capability to perform desired tasks.
Continuing training conducted beyond the initial training of a discipline, designed to maintain a level of proficiency by ensuring the canine team's capability to perform desired tasks.
Continuing training conducted beyond the initial training of a discipline, designed to maintain a level of proficiency by ensuring the canine team's capability to perform desired tasks.
Classification system based on the circumstances under which death occurred; includes accident, homicide, natural, suicide, and undetermined.
See photographic comparison.
a class name for various genera of filament, tow, or staple produced from fiber-forming substances which can be (1) polymers synthesized from chemical compounds, (2) modified or transformed natural polymers, or (3) glass.
Discussion—Acrylic, nylon, polyester, olefin, urethane, and polyvinyl are examples of fiber synthesized from chemical compounds. Cellulose-based fibers, such as acetate and rayons, and alginate fibers are examples of modified or transformed polymers.
a class name for various genera of fibers (including filaments) produced from fiber-forming substances which can be (1) polymers synthesized from chemical compounds [synthetic fibers], (2) modified or transformed natural polymers [regenerated fibers], and (3) minerals, for example, glasses.
The point where a needle has pierced the skin, usually associated with drug use.
a colored grain of smokeless powder to assist in the visual identification of a bulk reloading smokeless powder.
A gene or specific DNA sequence of known location on a chromosome or genome.
A gene or specific DNA sequence of known location on a chromosome; used as a point of reference in the mapping of other loci.
automated function where results above or below a specified threshold are reported with a defined result. For example, the instrument may report “ethanol below administrative threshold” or “0.000 g/210 L ethanol” for a response below 0.005 g/210 L. Another example may be reporting “Results greater than 0.400 g/210 L” or “Over Range” for a response above 0.400 g/210 L.
The presence of an odor/scent that impedes detection of the target odor/scent source.
The mass of an ion divided by its charge.
One of a number of high throughput DNA sequencing techniques. Also referred to as Next Generation Sequencing (NGS).
One of a number of high throughput DNA sequencing techniques. Also referred to as Next Generation Sequencing (NGS).
the original retrieved data irrespective of media (for example, if the recorded video from the DVR hard drive was downloaded to CD/DVD, that CD/DVD is defined as the master).
The determination that two samples are not distinguishable from each other given available data and/or information. When used in a DNA testing report, a match refers to genetic profiles that show the same types at all loci tested in common; a match statement does not confirm that an individual is the source of the DNA.
A mathematical value that indicates the degree of similarity between an unknown spectrum and a reference spectrum.
A mathematical value that indicates the degree of similarity between an unknown spectrum and a reference spectrum.
A pathway laid by a human subject whose scent matches the scent on the article presented to the canine.
A procedure where upon presentation of a comparison stimulus, an animal chooses the same stimulus amongst an array of stimuli. For example, a canine is presented with scent of Person X and then identifies the scent contributor amongst an array of persons.
The fuel that is first set on fire by the heat of ignition; to be meaningful, both a type of material and a form of material should be identified.
A specific biological fluid or tissue. Examples include blood, plasma, serum, urine, vitreous fluid, hair, and tissue.
the physical material, such as burned debris or clothing, which is being tested for ignitable liquids; also known as substrate.
the physical material, such as burned debris or clothing, which is being tested for ignitable liquids; also known as substrate.
dominant or background color component of a soil sample, soil aggregate, ped, clod, or horizon.
A positive or negative control that is prepared in the same or similar matrix as the case sample(s) or material
Megabyte (of digital storage) this normally refers to 1024*1024 (1,048,576) bytes in digital applications thoughothers may intend 1000*1000 or 1,000,000 bytes.
A widely used cryptographic hash function producing a 16-byte hash value, typically expressed in text format as a32-digit hexadecimal number. MD5 is commonly used to verify data integrity.
a feature or property of a sample that does not fall within the variation exhibited by the comparison sample, considering the limitations of the sample or technique, and therefore indicates the two samples do not share a common origin. The use of this term does not imply the formal application of statistics.
a feature or property of a sample that does not fall within the variation exhibited by the comparison sample, considering the limitations of the sample or technique, and therefore indicates the two samples do not share a common origin.
Discussion—The use of this term does not imply the formal application of statistics.
a feature or property of a sample that does not fall within the variation exhibited by the comparison sample, considering the limitations of the sample or technique, and therefore indicates the two samples do not share a common origin. The use of this term does not imply the formal application of statistics.
Quantity intended to be measured. VIMa
quantity intended to be measured
A physical quantity or property which is measured.
Quantity intended to be measured
Make a measurement.
quantity value representing a measurement resulth
h: Joint Committee for Guides in Metrology (JCGM), International vocabulary of metrology - Basic and general concepts and associated terms (VIM) (Sèvres, France: International Bureau of Weights and Measures [BIPM]- JCGM 200) available at https://www.bipm.org/en/publications/guides.
Process of experimentally obtaining one or more quantity values that can reasonably be attributed to a quantity.
process of monitoring the validity of the calibrations performed
System of coordinates that represent the geometry of the measured surface.NOTE If the nominal surface is a plane (or portion of a plane), it is common to use a rectangular coordinatesystem in which the axes form a right-handed Cartesian set, the X-axis being the direction of tracing co-linearwith the mean line, the Y-axis also lying on the nominal surface, and the Z-axis being in an outward direction(from the material to the surrounding medium).
Reference, with a stated value and associated measurement uncertainty, used to calibrate or verify measuring instruments or measuring systems
non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used (also uncertainty of measurement, uncertainty.)
Discussion—Measurement uncertainty includes components arising from systematic effects, such as components associated with corrections and the assigned quantity values of measurement standards, as well as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead, associated measurement uncertainty components are incorporated. The parameter may be, for example, a standard deviation called standard measurement uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability. Measurement uncertainty comprises, in general, many components. Some of these may be evaluated by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity values from series of measurements and can be characterized by standard deviations. The other components, which may be evaluated by Type B evaluation of measurement uncertainty, can also be characterized by standard deviations, evaluated from probability density functions based on experience or other information. In general, for a given set of information, it is understood that the measurement uncertainty is associated with a stated quantity value attributed to the measurand. A modification of this value results in a modification of the associated uncertainty.
element in the optical path of a MSP system that limits the area of illumination reaching the detector focal plane.