Definition of "silencer"

Something that silences

1. An attachment to a gun or an exhaust pipe that reduces the sound it emits  examples

2. The muffler of an internal combustion engine.  quotations  examples

   Quotations

   • Before the fitting of silencers to these locomotives was completed by the end of 1961, they were very noisy in operation, but the effect of the silencer has been remarkable.

     1962 April, P. W. B. Semmens, “The Netherlands Railways today”, in Modern Railways, page 241

3. Any of various devices to silence the humming noise of telegraph wires  examples

4. (genetics) Something that prevents gene expression  examples