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.
Known Sample
Known soil sample
Known Voice Signal
A voice signal from an individual who has been identified, or individuated in a waythat allows linking to additional, available information about that individual.
known writing
Of established origin used for comparison with questioned writing. Known writing may be collected or requested and can consist of exemplars or purported writing.
Label (Manufacturer's Sizing Label)
Labeled
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.
Laboratory
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.
Laboratory
The entity providing the analysis, including the staff and the physical facility.
laboratory‐developed test method
type of non-standard test method designed and used within a single laboratory or laboratory system
landscape mode
A horizontal orientation of a document or image.
laser printer
Nonimpact printer that uses a laser light source driven by digital signals to create images on a photoconductor (see 3.1.143 electrophotography). (ASTM F909)
Last
Last Known Position (Lkp) Point Last Seen (Pls)
Point on a map where the person was last identified or spotted by a witness.
Latent Impression
Latent Learning
Learning that takes place unintentionally, and does not manifest in overt behavior at that time, but may become evident at a later stage.
Latent Print
An impression or image of friction ridge skin left on a surface.
Law Enforcement Officer (LEO)
Any public employee whose duties primarily involve the enforcement or investigation of alleged or suspected violations of law.
law enforcement officer (LEO)
Any public employee whose duties primarily involve enforcement or investigation of laws.
Layering
The systematic process of removing debris from the top down and observing the relative location of artifacts at the fire scene.
Lead-Free Ammunition
lead-in mark
A visible, thin, elongated deposition of bullet wipe transferred to a surface as a bullet first makes contact with that surface at a shallow angle of incidence.
NOTE The lead-in mark is useful in establishing the entrance side of the projectile impact.
Learning Plateau
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.
leg
A large appendage typically on the right side of such characters as "R" and "K", usually formed with a downward movement.
Legacy
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.
letterpress
Relief printing using cast metal type, molded duplicate plates, or photo-polymer plates, which the imaged areas are raised above the non-printing areas, resulting in characters impressed into the substrate.
Level Of Uncertainty (Lou)
This characterizes the dispersion of values used for measuring dental age assessment based on the variation within the data.
Levels of Conclusion
Lift
lift
A product of an EDD examination. The developed image on the imaging film is preserved by applying fixing film to create a lift. (ANSI/ASB Std 044)
liftoff
The removal of one or more images of copy from the substrate by transferring to an intermediate member. (ASTM F221)
liftoff correction
The removal of a typed character by restriking with the same character while interposing an adhesive coated tape or sheet, thereby causing the imprinted character to adhere to the coating and be stripped from the record medium; then the intended character or space is placed therein.
ligature
In printing or writing, two or three characters linked to create a single letterform such that the terminal stroke of the first is the initial stroke of the second.
Light Microscope
Lights Out
Lignin
likelihood ratio
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.
Limit Of Detection
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.
Limit Of Detection
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.
Limit Of Detection (Lod)
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.
limit of detection (LOD)
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
limit of detection (LOD)
estimate of the lowest concentration of an analyte in a sample that can be reliably differentiated from blank matrix and meets identification criteria for the analytical method
Limit of Detection, Detection Limit, LOD
limit-of-detection
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.
limitation
A constraint to the examination, comparison, or opinion formation process (e.g., non-original documents, insufficient quantity or quality of material).
Limited Access Search Site
A site designed to test the canine's ability to search and indicate independently of the handler.
limited examinations
Limited examinations are partial analyses, comparisons, and/or processing that do not fully utilize the capabilities of a Forensic Service Provider (FSP).
Lincoln Index (LI)
Quantification technique to estimate the actual number of individuals based on the number of paired and unpaired bones.
line continuity
Uninterrupted writing. Discontinuity may be in the form of pen lifts, pen stops, hesitations, or patching.
line quality
The appearance of the written stroke caused by the basic movements and the manner of manipulating the writing instrument. Results from the combination of such factors as speed, rhythm, shading, and smoothness of movement. It may vary from good line quality that is smooth and fluent to poor line quality that is tremulous and erratic.
line spacing
The distance between successive lines of text, which for machine-generated documents is usually measured from baseline to baseline.