κρούω
κρούω
to strike, smite: to strike one against another, κρ. χεῖρας to clap hands, Eur.; κρ. τὰ ὅπλα πρὸς ἄλληλα Thuc., etc.:— κρ. τὸν πόδα (i. e. κρ. τὴν γῆν τῶι ποδί) in dancing, Eur.
κέραμον κρούειν to tap an earthen vessel, to try whether it rings sound: hence to examine, prove, Plat.
to strike a lyre with the plectron, Plat.
κρούειν τὴν θύραν to knock at the door on the outside, Xen., etc.
as a nautical term, in Mid., κρούεσθαι πρύμναν, like ἀνακρούεσθαι, to back a ship, Thuc.