Apperceive :: Apperceive (v. t.) To perceive; to comprehend.
Apperception :: Apperception (n.) The mind's perception of itself as the subject or actor in its own states; perception that reflects upon itself; sometimes, intensified or energetic perception..
Clapper :: Clapper (n.) 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..