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.
a device designed to cause a mechanical explosion by overpressure of the container due to a chemical reaction; generally produced by the mixing of commonly available chemicals or products. Discussion—Examples include the mixing of hydrochloric acid and aluminum foil; and mixing sodium hydroxide; water and aluminum foil.
The medical examiner, coroner, justice of the peace or other official who oversees the operation of a medicolegal death investigation office and/or system.
Medical examiner, coroner, justice of the peace or other official who oversees the operation of a medicolegal death investigation office and/or system.
The vertical airflow within buildings caused by the temperature-created density differences between the building interior and exterior or between two interior spaces. Also known as the stack effect.
The effect of heat on odor/scent such that the odor/scent rises and travels through the air in a manner affected by air movement and temperature through convection. The end effect is that odor/scent is detected in a place that is different from the source. This can happen indoors or outdoors.
An organic compound containing chlorine atoms.
the saturation or brilliance of a color, from 0 (no color) to ~8 (for vividly colored soils) or higher (for non-soil materials) in the Munsell color system.
the series of bands visible on the adsorbent layer after development.
A physical method of separation in which the components to be separated are distributed between two phases, one of which is stationary (stationary phase) while the other (the mobile phase) moves in a definite direction.
a separation technique in which the flow of solvent causes the components of a mixture to migrate differentially from a narrow initial zone over a planar, thinly-applied porous adsorptive medium.
The difference between the individual's date of birth and a specific later date. Note: Chronologic age may be expressed in varying degrees of precision and can be derived from computer programs that report age values using multiple significant digits. To correctly interpret and report results, consultation with a statistician may be necessary.
The age of an individual in years, months, and/or days, calculated as the difference between the individual’s date of birth and a specific later date.
The International Commission on Illumination. The color space that they defined iscalled CIELab. They have also developed a metric for color distance called E1976(Delta E) with 1976 indicating the version of the formula. They have developed moredetailed and precise distance metrics in later years. For more information, seehttp://en.wikipedia.org/wiki/Color_difference.
The Criminal Justice Information Services Division of the FBI.
See enhancement.
See enhance.
a group, set, or kind sharing common attributes. Examples provided in reference.)
the attribute(s) that establish membership in a class.
The nature and cause of the inconsistency raises immediate concerns regarding the quality of the footwear and tire
examiner’s/agency's work product.
The inconsistency is due to a problem which may affect the quality of the work but is not serious enough to cause immediate concern for the overall quality of the footwear and tire examiner’s/agency's work product.
The inconsistency is determined to have only minimal effect or significance, be unlikely to recur, is not systemic, and does not significantly affect the fundamental reliability of the footwear and tire examiner’s /agency's work.
The value of resolution (scanning or nominal) used to name (or identify) an acquisitionprocess or image, where the resolution is within a specified tolerance around that value.Example: A scanner is referred to as 500 ppi (class resolution) if the native scanningresolution is within 1% (5 ppi).
A form of learning in which the pairing of a previously neutral stimulus with a stimulus that elicits a response results in that neutral stimulus producing a similar response
the systematic arrangement of hairs into categories (for example, human, animal, somatic origin, ancestry) based on shared traits.
the systematic arrangement of persons or objects into categories (groups or classes) based on shared traits or characteristics
the systematic arrangement of hairs into categories (for example, human, animal, somatic origin, ancestry) based on shared traits.
A distinct and visible fire effect generally apparent on noncombustible surfaces after combustible layer(s) (such as soot, paint, and paper) have been burned away.
to the extent possible, a limited particulate environment. Discussion—For example, requirements would follow ISO 5 or Class 100 standard for air quality.
in computer forensics, to overwrite storage space on a medium with non-sensitive data, which may include overwriting not only the logical storage location of files, but may include all addressable locations.
Medical evaluation by a veterinarian of a live animal for medicolegal purposes.
NOTE The examination may include, but is not limited to, the assessment of behavior, body condition score and organ systems to identify and document an animal's overall condition at a point in time.
in computer forensics, a group of contiguous sectors on storage media, typically the smallest unit of allocation in a filesystem.
The canine handler's ability to correctly recognize and reward a desired behavior of the canine, or redirect or stop an undesired behavior.
a generic term for paint, lacquer, enamel, or other liquid or liquifiable material which is converted to a solid, protective, decorative, or combination thereof, film after application.
a generic term for paint, lacquer, enamel, or other liquid or liquefiable material that is converted to a solid, protective, or decorative film or a combination of these types of films after application.
Illumination from the precise direction of the imaging lens (e.g. either through the lens or with abeam-splitter in front of the lens).
either d- or l- cocaine; it should be noted that l-cocaine is the naturally occurring isomer found in the coca plant.
A standard that is an extensive compilation of provisions covering broad subject matter or that is suitable for adoption into law independently of other codes and standards.
A codec is a computer program that encodes and decodes a data signal, usually in acompressed format.
Algorithm designed to encode or decode a stream of digital audio data.
an algorithm to encode and decode digital data, typically to reduce the amount of data for transmission or storage.
Discussion—A codec is not a storage format, but may be required to interpret stored data.
A codec format is the data structure produced by a codec.
Coercion deals with compliance induced by physical or mental pressure. Examples may include use of force, threats, or intimidation.
in image and video analysis, a process used to extract visual information from an image by human evaluation.
Surface topography measurement method wherein the localization of interference fringes during ascan of optical path length provides a means to determine a surface topography map.
spectral artifacts that result from elastic scattering of the tube target characteristic X-rays by the sample.
Discussion—Because no energy is lost in elastic scattering, coherent scatter peaks occur at the same energies as the tube target characteristic X-rays.
the degree of visual difference that is evident between one soil color compared with another in close proximity.
Discussion—Within this practice, color contrast refers to color difference between evidentiary soil samples.