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.
See ignition temperature.
the energies associated with the transitions of the K, L, and M shell electrons.
Discussion—Each element has characteristic energies of transitions of electrons between shells.
a structure produced by interlooping one or more ends of yarn or comparable material.
the level of information, qualifications, and experience needed to perform assigned tasks.
Discussion—Knowledge refers to acquired understanding of the principles and practices related to a particular job, skills refer to acquired analytical and psychomotor behaviors, and abilities refer to the talents, observable behaviors, or acquired dexterity.
of established origin associated with the matter under investigation.
Discussion—- Known soil samples are intentionally collected, typically from crime scene or alibi locations, for comparison to a questioned soil sample. Soils are heterogeneous mixtures of organic matter and minerals that vary with depth and across the landscape. Typically, more known samples are needed to represent the range of variation in soils than are required for manufactured materials.
of established origin or identity associated with a matter of interest.
An item of footwear or tire from a specific source that is compared to a questioned footwear or tire impression.
in facial identification and image analysis, an image of an individual or object associated with a known or claimed identity or object and recorded electronically or by other medium (also known as exemplars). (Compare questioned image.)
Biological material for which the identity of the donor is established and used for comparison purposes.
known samples of geological material are intentionally collected, typically from crime scene or alternate locations, for comparison to a questioned sample.
Discussion—Geological materials are typically more heterogeneous than manufactured materials, so a greater number of known samples of geological material are needed to represent the range of variation (see Guide E3272). Reference sample and control sample are synonyms of known sample.
a coating sample of established origin.
known soil samples are intentionally collected, typically from crime scene or alternate locations, for comparison to a questioned soil sample.
Discussion—Soils are heterogeneous mixtures of organic matter and minerals that vary vertically with depth and horizontally across the landscape. Typically, a greater number of known soil samples are needed than manufactured materials to represent the range of variation (see Guide E3272). Reference sample and control sample are synonyms or sub-types of known soil samples.
A voice signal from an individual who has been identified, or individuated in a waythat allows linking to additional, available information about that individual.
Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.
body that performs one or more of the following activities: testing; calibration; sampling, associated with subsequent testing or calibrationNote 1 to entry: In the context of this document, laboratory activities refer to the three above-mentionedactivities.
The entity providing the analysis, including the staff and the physical facility.
Process of stamp manufacturing using “laserable rubber” (pre-vulcanized natural rubber) and laser engraving to cut the image to form the die of the stamp.
Point on a map where the person was last identified or spotted by a witness.
Learning that takes place unintentionally, and does not manifest in overt behavior at that time, but may become evident at a later stage.
An impression or image of friction ridge skin left on a surface.
Any public employee whose duties primarily involve the enforcement or investigation of alleged or suspected violations of law.
The systematic process of removing debris from the top down and observing the relative location of artifacts at the fire scene.
ammunition incorporating a primer that does not contain lead.
A period in which early progress in learning appears to have stopped and improvement is at a standstill. The plateau is followed by a new period of progress.
Indicates that the transaction element was valid in previous versions of the standard.Systems claiming conformance to this version of the standard shall only use the elementwhen transmitting information stored prior to the adoption of this version of the standard.
This characterizes the dispersion of values used for measuring dental age assessment based on the variation within the data.
in facial identification, a verbal or numeric scale that indicates the level of confidence regarding identification or exclusion of a subject.
A product of an EDD examination. The developed toner image on the imaging film is preserved by applying fixing film to create a lift.
An adhesive or other medium used to capture and preserve an impression.
Use of a xenon flash in the manufacturing of a flat die stamp. Numerous light bursts are used to seal the background of the stamp pad leaving open micropores in the area of the flat die to print the text.
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.