n. & v.
n. 1 a check or restraint. 2 a strap etc. fastened to the bit and passing under a horse's lower jaw, used as a check. 3 an enclosing border or edging such as the frame round the top of a well or a fender round a hearth. 4 = KERB.
v.tr. 1 restrain. 2 put a curb on (a horse). curb roof a roof of which each face has two slopes, the lower one steeper.
[ ME f. OF courber f. L curvare bend, CURVE ]