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 finely ground, inorganic or organic, insoluble, dispersed particle. Besides color, a pigment can provide many of the essential properties of paint, such as opacity, hardness, durability, and corrosion resistance. The term pigment includes extenders.
A finely ground, inorganic or organic, insoluble, and dispersed particle; besides color, pigments provide many of the essential properties of paint such as opacity, hardness, durability, and corrosion resistance; the term pigment includes extenders
A finely ground, organic or inorganic, insoluble, and dispersed particle. Besides color, a pigment can provide many of the essential properties of paint, such as opacity, hardness, durability, and corrosion resistance (see also effect pigment).
A finely ground, inorganic or organic, insoluble, and dispersed particle; besides color, pigments provide many of the essential properties of paint such as opacity, hardness, durability, and corrosion resistance; the term pigment includes extenders.
a finely-divided insoluble material used to deluster or color fibers (for example, titanium dioxide and iron oxide).
Clusters of pigment granules.
clusters of pigment granules.
The relative abundance of pigment granules in the hair cortex as described along a continuum (for example, sparse, medium, heavy).
the relative abundance of pigment granules in the hair cortex as described along a continuum (for example, sparse, medium, heavy).
The pattern or arrangement of the pigment granules in the hair shaft, such as uniform, peripheral, one-sided, variable, or central.
the pattern or arrangement of the pigment granules in the hair shaft, such as uniform, peripheral, one-sided, variable, or central.
Small particles in hair composed of melanin that impart color. DiscussionMelanin is a natural pigment of which two forms, eumelanin (brown to black) and phaeomelanin (reddish brown to yellow), determine the color of human and animal hair.
small particles in hair com- posed of melanin that impart color.
Discussion—Melanin is a natural pigment of which two forms, eumelanin (brown to black) and phaeomelanin (reddish brown to yellow), determine the color of human and animal hair.
A hair disorder causing hairs to appear ringed or banded due to the alternating light and dark bands in the hair shaft; the dark bands are a manifestation of abnormal air spaces in the cortex.
a hair disorder causing hairs to appear ringed or banded due to the alternating light and dark bands in the hair shaft. The dark bands are a manifestation of abnormal air spaces in the cortex.
A hair disorder characterized by the hair shaft being flattened and twisted 180 degrees numerous times along its axis; it is usually found at irregular intervals along the shaft.
a hair disorder characterized by the hair shaft being flattened and twisted 180 degrees numerous times along its axis. It is usually found at irregular intervals along the shaft.
See ignition temperature.
a microscope equipped with two polarizing filters, one below the stage (the polarizer) and one above the stage (the analyzer).
In facial identification, an intrinsic rotation of the head about a horizontal left-to-right (lateral) axis measured in degrees
In facial identification, an intrinsic rotation of the head about a horizontal left-to-right (lateral) axis measured in degrees. DISCUSSIONFrontal poses have a pitch angle of 0. Positive angles represent faces looking down (a counter-clockwise rotation around the axis). The pitch axis is typically defined as the X-axis (positive to the right).
Personal Identity Verification.
The process of combining counts from adjacent pixels in a CCD detector during readout
The process of combining counts from adjacent pixels in a CCD detector during readout.
A fingerprint image resulting from the touching of one or more fingers to a livescanplaten or paper fingerprint card without any rolling motion.
Emitted or observed light in which the electric field vibrates in one direction in a single plane
light in which the electric field vibrates in one direction in a single plane.
The friction ridge skin on the feet (soles and toes).
Any of a wide range of natural or synthetic organic materials of high molecular weight that can be formed by pressure, heat, extrusion, and other methods into desired shapes.
Material added to plastics to impart flexibility by creating spaces between the polymer chains and lowering the inter- and intra-chain attractive forces, allowing freer movement of the chains. DiscussionPlasticizers are used in pressure sen- sitive backings (particularly PVC) and some adhesives to lower the glass-transition temperature and allow use at sub-ambient temperatures.
A high explosive in a pliable plastic matrix; examples include Composition C-4 (a white plastic explosive containing primarily RDX) and Semtex (a plastic explosive containing a mixture of PETN and RDX).
Blades with nearly equal length and breadth and of a thickness substantially less than the width
Blades with nearly equal length and breadth and of a thickness substantially less than the width.
Recorded material viewed and heard as recorded, facilitated by camcorder, cassette recorder, or other device
Recorded material viewed and heard as recorded, facilitated by camcorder, cassette recorder, or other device.
In audio and video analysis, the process of determining the most suitable equipment and settings for producing the highest quality output signal
In audio and video analysis, the process of determining the most suitable equipment and settings for producing the highest quality output signal.
The property of exhibiting different colors, especially three different colors, when viewed along different axes by plane polarized light. The phenomenon of substances showing different absorption colors in different vibration directions. The observed colors change with the orientation of the crystal and can be seen only with plane polarized light
(1) the number of single yarns twisted together to form a plied yarn, or the number of plied yarns twisted together to form cord; (2) an individual yarn in a plied yarn or cord; (3) one of a number of layers of fabric; (4) the number of layers of fabric as a shirt collar, or of cord in a tire
(1) the number of single yarns twisted together to form a plied yarn, or the number of plied yarns twisted together to form cord; (2) an individual yarn in a plied yarn or cord; (3) one of a number of layers of fabric; (4) the number of layers of fabric as a shirt collar, or of cord in a tire.
Crystals resembling pliers, generally X-shaped
Crystals resembling pliers, generally X-shaped.
The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column.
Portable Network Graphics.