Webster's Revised Unabridged Dictionary · 1913

Clapper

Clapper , noun

1.
A person who claps.
2.
That which strikes or claps, as the tongue of a bell, or the piece of wood that strikes a mill hopper, etc. See Illust. of Bell.
Collocations (1)
Clapper rail (Zoology) , an Americam species of rail (Rallus scepitans).

Clapper , noun

[French clapier.]

A rabbit burrow. [Obsolete]