Tracer may refer to:

Science

* Flow tracer, any fluid property used to track fluid motion *

Fluorescent tracer Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

, a substance such as 2-NBDG containing a fluorophore that is used for tracking purposes *

Histochemical tracer A histochemical tracer is a compound used to reveal the location of cells and track neuronal projections. A neuronal tracer may be retrograde, anterograde, or work in both directions. A retrograde tracer is taken up in the terminal of the neuron an ...

, 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 found in nature *

Radioactive tracer A radioactive tracer, radiotracer, or radioactive label is a chemical compound in which one or more atoms have been replaced by a radionuclide so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by t ...

, a substance containing a radioisotope that is used for tracking purposes * TRACER (cosmic ray detector) (Transition Radiation Array for Cosmic Energetic Radiation), a balloon-borne cosmic ray detector * Tracers, a colloquialism for visual trailing, often experienced in connection with drug use * TRACERS ( Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites), a pair of orbiters to study the origins of the solar wind and how it affects Earth

Military

* Tracers, tracer ammunition, special bullets that burn brightly to enable the shooter to follow the bullets' trajectories *

Tactical reconnaissance and counter-concealment-enabled radar The United States Army tactical reconnaissance and counter-concealment-enabled radar – TRACER is a mid-range, long wavelength synthetic aperture radar (SAR) system that provides all-weather persistent surveillance developed by the United States A ...

(TRACER), a radar system developed by the United States Army * Grumman E-1 Tracer, a carrier-borne early warning aircraft used by the United States Navy in the 1960s * Tactical Reconnaissance Armoured Combat Equipment Requirement, a joint British–American scout vehicle

Arts and entertainment

Music

* Tracer (band), an Australian rock band * ''Tracer'' (album), a 2012 album by Teengirl Fantasy * "Tracers", song by Ash (band) from '' A-Z, Vol.1'' 2010 * "Tracers", song by Miracle Fortress from '' Was I the Wave?'' 2011 * "Tracers", song by Trans-Siberian Orchestra from '' Night Castle'' 2009

Films

* ''Tracer'' (film), a 2016 Vietnamese film * ''Tracers'' (film), a 2015 American film

Video games

* ''Tracer'' (game), a 1995 action-puzzle video game * ''Tracer'', a 1976 Sega arcade video game * Tracer, leader of the Eliminators in '' The Warriors'' * Tracer (''Overwatch''), a player character from the video games ''Overwatch'' and ''Heroes of the Storm'' * Tracer Tong, a character from the video game series ''

Deus Ex ''Deus Ex'' is a series of role-playing video games, set during the mid 21st century. Focusing on the conflict between secretive factions who wish to control the world by proxy, and the effects of transhumanistic attitudes and technologies in a ...

Comics and comic strips

* Tracer (DC Comics), a DC Comics character * Tracer (Marvel Comics), a Marvel Comics supervillain * Tracer Bullet, one of Calvin's alter egos in ''Calvin and Hobbes''

Television

* ''Tracer'' (TV series), a 2022 South Korean television series

Transportation

Mercury Tracer The Mercury Tracer is an automobile manurfactured and marketed by Ford's Mercury division for model years 1987-1999, over three generations in three- and five-door hatchback, four-door sedan, and five-door station wagon configurations. The fir ...

, an automobile * Tracer (bus), the bus system for Tracy, California