2. (Mech.) A cotter or split pin, as in a slot in a bolt, to
prevent retraction; a linchpin; a pin fastening the
cap-square of a gun.
{Forelock bolt}, a bolt retained by a key, gib, or cotter
passing through a slot.
{Forelock hook} (Rope Making), a winch or whirl by which a
bunch of three yarns is twisted into a standard. --Knight.
{To take} {time, or occasion}, {by the forelock}, to make
prompt use of anything; not to let slip an opportunity.
Time is painted with a lock before and bald behind,
signifying thereby that we must take time by the
forelock; for when it is once past, there is no
recalling it. --Swift.
On occasion's forelock watchful wait. --Milton.