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 microscope that employs light in the visible portion of the electromagnetic spectrum.
in facial identification, an automated conclusion based upon threshold scores with no human involvement.
the majority non-carbohydrate portion of wood; it is an amorphous polymeric substance that cements cellulosic fibers together and is the principal constituent of woody cell walls.
The probability of the evidence under one proposition (hypothesis), divided by the probability of the evidence under an alternative, mutually exclusive proposition (hypothesis). The magnitude of its value expresses the weight of the evidence.
An estimate of the lowest concentration of an analyte in a sample that can be reliably differentiatedfrom blank matrix and identified by the analytical method.
An estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and identified by the analytical method.
An estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and identified by the analytical method.
An estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and identified by the analytical method
An estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and identified by the analytical method.
Estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and identified by the analytical method
Estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and meets identification criteria.
lowest amount of an analyte that is detectable with a given confidence level.
1) For a test, the point at which the sensitivity of the test is such that the quantity or concentration of a component present is insufficient to produce a positive test result or be detected. 2) For instrumental analysis, the point below which it is not possible to reliably distinguish analytical signal data from instrument background noise; typically defined as three times the standard deviation of the average background noise; The LOD may be calculated to aid in setting an analytical threshold for the reporting and interpretation of alleles in a DNA profile electropherogram.
A site designed to test the canine's ability to search and indicate independently of the handler.
Quantification technique to estimate the actual number of individuals based on the number of paired and unpaired bones.
Utilization of a canine to scent discriminate among a predetermined sequence of items with target odor/scent(s) versus non-target odor/scent(s).
Consists of finding the best-fit linear relationship between the instrument response (Y) and the concentration of the analyte in the calibrator (X)
Method of estimating stature based on a statistical procedure for describing a relationship between stature and bone dimension that can be used to predict the former from the latter.
The borders defining the differences in fire effects on materials between the affected area and adjacent, less-affected areas.
The nonrandom association, in a population, of alleles at different loci.
Document(s) exposed to or immersed in liquid(s).
Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.
the time over which the energy dispersive X-ray spectroscopy electronics are available to accept and process incoming X-rays. Live time is often expressed as a percentage of real time.
the time during which an energy dispersive X-ray spectrometer is available to accept and process incoming X-rays.
Discussion—Live time is often expressed as a percentage of real time, in seconds.
A person’s recorded height, which may be derived from various sources including self-reported stature, family remembrance, or direct measurement.
Utilization of a trailing canine to determine if a matching scent is located at a specific site or not by using a scent article.
Utilization of a trailing canine to determine if an associated scent is located at a specific site or not by using a scent article.
A test involving one odor per 0.3 meters (1 foot), 1 minute per odor.
A unique physical location of a gene (or specific sequence of DNA) within a chromosome; the plural of locus is loci (which is pronounced low-sigh).
A unique physical location on the DNA molecule.
A physical location of a gene or specific sequence of DNA on a chromosome.
A unique physical location of a gene (or specific sequence of DNA) on a chromosome.
a record of actions, events, and related data.
in computer forensics, an accurate reproduction of information contained within a logical volume (for example, mounted volume, logical drive assignment, and so forth).
Discussion—Logical acquisitions or copies may not reproduce deleted data, or data otherwise not accessible easily by a user.
in computer forensics, a partition or a collection of partitions acting as a single entity that has been formatted with a filesystem.
descriptive term for encoding and decoding processes and procedures in which the output of the decoding procedure(s) is identical to the input to the encoding procedure(s).
a data reduction process that is completely reversible, such that all of the original data can be retrieved in its original form.
descriptive term for encoding and decoding processes that are not lossless.
a data reduction process that is not completely reversible, and some original data is irretrievably lost.
A term for DNA or DNA analysis of small quantities of DNA that require modification to PCR protocols to enhance amplification success of the target molecule.
a dichroic mirror that is coated with an IR reflective surface.
Discussion—Such glass is suitable for use as a sample support when performing IR reflection techniques.
An explosive that has a reaction velocity of less than 1000 m/sec (3000 ft/sec).
energetic materials that function by deflagration.
a descriptive of an explosive that undergoes incomplete reaction (or detonation) of the material as designed.
A mass spectrometer limited to nominal mass resolution measurements (see nominal mass).
A slow rate of pressure rise or low-force explosion characterized by a pushing or dislodging effect on the confining structure or container and by short missile distances.