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 definitive procedure that produces a test result
A term intended to encompass any report containing the description of items submitted to a laboratory, as well as any results of testing and examinations that may have occurred.
The determination, by technical means, of properties, performance or elements of materials, products, services, systems, or environments, which may involve application of established scientific principles and procedures. Testing typically applies to materials, products or processes.
A rough surface or shallow design added to surfaces of a mold through the process of chemical etching or hand struck stippling that is transferred to the footwear during the molding process. Texture is unique to specific molds.
See plume
The increase in length, volume, or surface area of a body with rise in temperature.
The properties of a material that characterize its rate of surface temperature rise when exposed to heat; related to the product of the material's thermal conductivity (k), its density (_), and its heat capacity (c).
A mixture comprised of a metal oxide and powdered metal that reacts with extremely high temperature and produces molten metal and slag. DISCUSSION: The most common thermite mixture is composed of iron oxide and powdered aluminum.
The branch of physics that deals with the relationship between heat and other forms of energy.
The study of the science, methodology, and practice of temperature measurement.
a synthetic material that softens or melts at high temperatures.
Plastic materials that soften and melt under exposure to heat and can reach a flowable state.
A synthetic material that softens or melts at high temperatures
Plastic materials that are hardened into a permanent shape in the manufacturing process and are not commonly subject to softening when heated; typically form char in a fire.
For the purpose of this guide, a sample that is 2 m or thicker
the optical path through a fiber used for the calculation of birefringence.
Distance from one surface of a tape, backing, or adhesive to the other, usually expressed in the United States as thousandths of an inch, or the industrial vernacular as 'mils' which represents thousandths of an inch (that is, 1 mil = 0.001 in.).
The optical path through a fiber used for the calculation of birefringence
For the purpose of this guide, a sample with a thickness of less than 2 m
The series of spots visible on the adsorbent layer after development
A technique whereby components of a specimen mixture are separated based on differences in solubility between a stationary phase coated on a plate and a mobile phase present as vapors in a development tank.
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
In facial identification, images used in facial recognition (FR) or facial identification (FI) that were not captured by the agency performing the comparison (for example, family snapshots of a missing person).
In facial identification, images used in facial recognition (FR) or facial identification (FI) that were not captured by the agency performing the comparison (for example, family snapshots of a missing person)
a slender strong strand or cord made by plying or twisting yarns, typically used for stitching.
A slender strong strand or cord made by plying or twisting yarns, typically used for stitching
An impression made on surfaces such as soil, sand, snow or mud with dimensions of length, width, and depth.
An impression made on surfaces such as soil, sand, snow or mud with dimensions of length, width, and depth.
DetectionThe minimum and maximum concentration of a chemical vapor that can be detected by a canine or an instrument. BehavioralThe level of stimulation above or below which learning and/or performance is impaired.
A value, based on a background sample study, below which the number of pGSR particles identified cannot be distinguished from background levels and thus cannot be reliably interpreted as associated with the discharge of a firearm or contact with a source of pGSR.
Small digital storage device that uses flash memory and a universal serial bus (USB) connection to interface with a computer
Graphic representation of the events in a fire incident displayed in chronological order.
A electronic device used to correct timing inconsistencies, stabilize, and synchronize video signals for optimum quality.
A electronic device used to correct timing inconsistencies, stabilize, and synchronize video signals for optimum quality
Process by which images are recorded at less than the standard rate of frames per second (National Television System Committee (NTSC) 29.97; Phase Alternating Line (PAL) 25.00) thus extending the period of time that can be covered by the storage medium.
Process by which images are recorded at less than the standard rate of frames per second (National Television System Committee (NTSC) 29.97; Phase Alternating Line (PAL) 25.00) thus extending the period of time that can be covered by the storage medium
In video analysis, a feature of digital video recorders (DVRs) that allows the equipment to adhere to data retention policies that may be mandated in certain parts of the world which results in video data becoming inacces- sible after a certain date.
In video analysis, a feature of digital video recorders (DVRs) that allows the equipment to adhere to data retention policies that may be mandated in certain parts of the world which results in video data becoming inaccessible after a certain date
Process of relating images, audio, or other data to one another in a chronologi- cally ordered succession.
Process of relating images, audio, or other data to one another in a chronologically ordered succession
In computer forensics, a point in time with respect to system time used by a file system to annotate creation, access or modification of file system objects.
In computer forensics, a point in time with respect to system time used by a file system to annotate creation, access or modification of file system objects
the most distal end of a hair shaft.
The contact area of a tire tread against a flat surface when under load, also known as a contact patch.
See aspect ratio.
Organization responsible for recovering tissues from tissue donors.
Any solid biological specimen that is generally weighed for analysis (e.g., brain, liver, muscle, hair, bone, meconium).
See vaccine titer.
See vaccine titer.
A thick strip of rubber that, in some footwear designs, is placed around the front perimeter of the footwear surrounding the toe area.