Resonator coil

From Memory Alpha, the free Star Trek reference

A resonator coil is a component of a starship.

After being trapped inside a subspace pocket by a subspace sinkhole in 2375, Tuvok, Tom Paris, and Noss salvaged a pair of resonator coils from one of the ships crashed on their planet. On the way back to their shelter, they were attacked by scavengers and the coils were stolen. (VOY: "Gravity")