Tracer
Tracer Tra"cer, n. One who, or that which, traces. [1913 Webster]

2. A person engaged (esp. in the express or railway service) in tracing, or searching out, missing articles, as packages or freight cars. [Webster 1913 Suppl.]

3. An inquiry sent out (esp. in transportation service) for a missing article, as a letter or an express package. [Webster 1913 Suppl.]

4. (Mil.) a type of ammunition that emits light or smoke as it moves toward its target, providing a visible path of the projectile in flight so that the point of impact may be observed; -- called also {tracer ammunition}. [PJC]

5. (Mil.) the chemical substance used in tracer ammunition to cause it to be visible in flight. [PJC]

6. a chemical substance with properties, such as radioactivity or fluorescence, which make it easily measurable, used to observe the movements of chemically related substances through a biological, physical, or chemical system; -- in biochemistry, also called {labeled compounds}.

Note: Radioactive tracers are used, for example, to measure the retention or distribution of residues of drugs after administration to an animal, to determine the type and rate of metabolism; also, to measure the rate of motion of molecules in electrophoresis or the leakage of small quantities of material from a container. Small fluorescent tracers may be attached in many cases to macromolecules such as proteins or nucleic acids, allowing the motions of such macromolecules to be easily observed by their acquired fluorescence, without appreciably changing their properties. In biological and biochemial systems the common radioactive isotopes used in tracers are carbon-14, tritium (hydrogen-3), sulfur-35, phosphorus-32, and iodine-131; other isotopes are also used, including non-radioactive isotopes such as carbon-13. [PJC]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • tracer — [ trase ] v. <conjug. : 3> • XVe; tracier XIIe; lat. pop. °tractiare, class. trahere « tirer, traîner » I ♦ V. tr. 1 ♦ Vx Suivre à la trace, poursuivre. 2 ♦ (mil. XVIe) Indiquer et ouvrir plus ou …   Encyclopédie Universelle

  • Tracer — may refer to: *Histochemical tracer, a substance used for tracing purposes in histochemistry, the study of the composition of cells and tissues *Isotopic tracer, a substance with an isotope that has been enriched to a greater level than that… …   Wikipedia

  • tracer — Tracer. v. act. Tirer les premieres lignes d un dessein, d un plan, sur le papier, sur la toile, sur le terrein. Tracer un plan. tracer un dessein. tracer une allé, un parterre, un fort, un bastion, des travaux &c. tracer de la tapisserie. tracer …   Dictionnaire de l'Académie française

  • tracer — Tracer, Inuestigare, Vestigare. Que les gens de village dient tracher. Tracer aussi est grossierement peindre et desseingner les traicts qu on doibt suyvre à faire quelque ouvrage à l esguille sur cannevas ou au pinceau sur autre chose, Delineare …   Thresor de la langue françoyse

  • Tracer — [tre̱ißer; aus engl. tracer = Aufspürer] m; s, : Bezeichnung für radioaktive Markierungsstoffe, mit deren Hilfe u.Tracera. biochemische Vorgänge im Organismus verfolgt werden können …   Das Wörterbuch medizinischer Fachausdrücke

  • tracer — (n.) c.1500, one who tracks or searches, agent noun from verb form of TRACE (Cf. trace) (n.1). Meaning bullet whose course is made visible is from 1910 …   Etymology dictionary

  • tračer — trȁčer m DEFINICIJA reg. onaj koji trača ETIMOLOGIJA vidi trač …   Hrvatski jezični portal

  • tracer — A form (Form 1510, Mail Loss/Rifling Report) that customers fill out to locate delayed or undelivered mail …   Glossary of postal terms

  • tracer — ► NOUN 1) a bullet or shell whose course is made visible by a trail of flames or smoke, used to assist in aiming. 2) a substance introduced into a system so that its subsequent distribution can be followed from its colour, radioactivity, or other …   English terms dictionary

  • tracer — [trās′ər] n. 1. a person or thing that traces; specif., a) a person whose work is tracing drawings, designs, etc. on transparent paper b) a person whose work is tracing lost or missing articles, persons, etc. c) an instrument for tracing designs… …   English World dictionary

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