Answer: bitting

AnswerCrossword Clue
BITTINGCurbing a horse.
bittingto wrap (a cable) around a bitt to secure it
bittingan indentation of a key
bittingstrong post of wood or iron projecting, usually in pairs, above the deck of a ship, used for securing cables, lines for towing, etc.
bittingone of the indentations on the bit of a key