Tracer

Tracer may refer to:

Science

Flow tracer, any fluid property used to track fluid motion
Fluorescent tracer, a substance such as 2-NBDG containing a fluorophore that is used for tracking purposes
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 found in nature
Radioactive tracer, 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 solar wind

Tracers, tracer ammunition, special bullets that burn brightly to enable the shooter to follow the bullets' trajectories
Tactical reconnaissance and counter-concealment-enabled radar (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

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