- noun a device behind a mole which widens a drain
Cars & Driving
- noun a device in a drum brake system (either hydraulic or mechanical) which forces the shoes apart into contact with the drum
- That which serves to expand.
- A circuit or device which automatically increases the volume range of an audio frequency signal. It works, essentially, to reverse the effect of volume compression, thus restoring the volume range of the original program. Also called volume expander.
- A circuit or device whose output has a greater amplitude range than its input.