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 origins of the solar wind and how it affects Earth

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