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.
The accumulation and evaluation of test data within the laboratory for developing the laboratory standard operating procedures and demonstrating that the established protocols for the technical steps of the test and for data interpretation perform as expected in the laboratory. The parameters (e.g., any variable that impacts interpretation) included in a test protocol used by the laboratory should be supported by validation studies conducted with samples of known origin similar to the types of samples routinely accepted and tested by the laboratory
The acquisition of test data within the laboratory to verify the functionality of the system, the accuracy of statistical parameters, the appropriateness of analytical and statistical parameters, and the determination of limitations of the system
The accumulation of test data within the laboratory for developing the laboratory standard operating procedures and demonstrating that the established protocols for the technical steps of the test and for data interpretation perform as expected in the laboratory.
an in-depth educational or training program that offers a period of supervised practical experience in a forensic science setting
an in-depth educational or training program that offers a period of supervised practical experience in a forensic science setting.
International Criminal Police Organization.
The estimation of the value of a sampled function at an arbitrary ordinal using the closest samples.
A Category 1 scoring function. The score is explainable and has quantifiable meaning.
Explanations for the observations, data, and calculations.
Also referenced in ANSI/ASB 040 Standard for Forensic DNA Interpretation and Comparison Protocols, ANSI/ASB 038 Standard for Internal Validation of Forensic DNA Analysis Methods, ANSI/ASB 015-24 Standard for Examining Friction Ridge Impressions, ANSI/ASB Best Practice Recommendation 166 Best Practice Recommendation for Comparison and Evaluation of Friction Ridge Impressions, ANSI/ASB 175 Standard for Interpreting, Comparing and Reporting DNA Test Results Associated with Failed Controls and Contamination Events, ANSI/ASB 123 Standard for Routine Internal Evaluation of a Laboratory’s DNA Interpretation and Comparison Protocol, ANSI/ASB Best Practice Recommendation 165 Best Practice Recommendation for Analysis of Friction Ridge Impressions, ANSI/ASB 167 Standard for Reporting Results from Friction Ridge Examinations
A qualitative description of the DNA data (e.g., partial data, mixture data).
Occurring among different species.
Between members of different species
In classical conditioning, the time elapsed between the conditioned stimulus and the unconditioned stimulus. In habituation, the time between exposures to a stimulus.
A schedule in which reinforcement is delivered on the basis of the amount of time before a response can be reinforced. The interval may be fixed or variable.
Organization, performance and evaluation of measurements or tests on the same or similar items within the same laboratory in accordance with predetermined conditions.
Also reference in ANSI/ASTM E3255-21 Standard Practice for Quality Assurance of Forensic Science Service Providers Performing Forensic Chemical Analysis, ANSI/ASTM E1732-24e1 Standard Terminology Relating to Forensic Science, ANSI/ASB 153 Standard Practices for Proficiency Testing for Forensic Toxicology Laboratories and Breath Alcohol Programs.
Occurring within the same species.
For the purpose of Chapter 29, the terms site and scene will be jointly referred to as the investigation site, unless the particular context requires the use of one or the other word.
A group of individuals working on behalf of an interested party to conduct an investigation into the incident.
In MS, the ratio of the instrument responses between two previously identified diagnostic ions.
In MS, the ratio of the instrument responses between two previously identified diagnostic ions.
The physicochemical process of producing a gas-phase ion. In the mass spectrometer this typically occurs within the ion source. Several mechanisms of ionization exist such as chemical and electron ionization.
The physicochemical process of producing a gas-phase ion. In the mass spectrometer this typically occurs within the ion source. Several mechanisms of ionization exist such as chemical and electron ionization.
Direct or indirect alteration or interference in the instrument response due to the presence of co-eluting compounds
International Phonetic Alphabet
Iris Exchange Program. This is a program at NIST in support of iris-based applicationsbased on standardized interoperable iris imagery. See http://www.nist.gov/itl/iad/ig/irex.cfm
A thin, colored, approximately circular structure surrounding the pupil of the eye thatcontains features used for identification of individuals.
International Organization for Standardization.
A line on a diagram connecting points of equal char depth.
A method of separating amphoteric molecules with minor differences in isoelectric points (pI). IEF can be used with several different enzyme systems including Phosphoglucose Isomerase (PGI), Erythrocyte Acid Phosphatase (EAP), Superoxide Dismutase (SOD) or Tetrazolium Oxidase (TO), Albumin (in conjunction with Western Blot), Mannose Phosphate Isomerase (MPI), Carbonic Anhydrase I (CAI) and Hemoglobin (Hb).
Isomers having the same number of each isotopic atom but differing in their positions.
a characteristic of an object in which the refractive index remains constant irrespective of the direction of propagation or vibration of the light through the object.
Object, substance or material that is collected, derived, or sampled as part of the forensic process.
Acronym for the Information Technology Laboratory of NIST. Seehttp://www.nist.gov/itl/
International Union of Pure and Applied Chemistry. See http://www.iupac.org
JPEG File Interchange Format. See http://www.jpeg.org
A statement that describes a specific job task, lists the items necessary to complete the task, and defines measurable or observable outcomes and evaluation areas for the specific task.
The preferred SI unit of heat, energy, or work. A joule is the heat produced when one ampere is passed through a resistance of one ohm for one second, or it is the work required to move a distance of one meter against a force of one newton. There are 4.184 joules in a calorie, and 1055 joules in a British thermal unit (Btu). A watt is a joule/second. [See also British Thermal Unit (Btu), and Calorie.]
Image compression and storage format specified by the Joint Photographic ExpertsGroup. It is discrete cosine transform-based.
Image compression and storage format specified by the Joint Photographic ExpertsGroup. It is a wavelet-based method.
A trial where jurors sit as the trier of fact.
The trained person who undertakes husbandry duties.
a class of sulfur-containing fibrous proteins that forms the foundation of outgrowth tissue from the epidermis, such as hair, nails, feathers, and horns.
The notch or groove in bone, tooth, or cartilage made by an object that is edged, pointed, or beveled.
A verbal or physical action by the canine handler which causes a detector canine to change its actions or to respond to an area or item whether target odor/scent is present or not. (See cueing.)
unit used to measure the energy of X-rays emitted from atoms when excited by the electron beam of an SEM.
Discussion—By definition, one electron volt is the amount of energy gained (or lost) by the charge of a single electron moving across an electric potential difference of 1 V. One kilo electron volt is 1000 eV.
A measurement of energy release rate.
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.