Warp signature

A warp signature is a disruption in space caused by the passage of a starship at warp speeds. Warp signatures can be detected by sensors and used to track the passage of ships. Different ships also have unique warp signatures, and the warp engines of certain races tend to be within a certain range allowing the identification of the vessel that left the signature.

Following an attack on the USS Enterprise-D in 2370 the ships long-range sensors were reconfigured to detect the specific warp signature of the assailant. (TNG comic: Strategy)