BREASTWHEEL n.
A water wheel, on which the stream of water strikes neither so high as in the overshot wheel, nor so low as in the undershot, but generally at about half the height of the wheel, being kept in contact with it by the breasting. The water acts on the float boards partly by impulse, partly by its weight.…
CLAP v. 2 definitions
To strike; to slap; to strike, or strike together, with a quick motion, so, as to make a sharp noise; as, to clap one's hands; a clapping of wings. Then like a bird it sits and sings, And whets and claps its silver wings. Marvell.