lock

Concise Oxford English Dictionary © 2008 Oxford University Press:
lock1

▶noun

• 1 a mechanism for keeping a door, lid, or container fastened, typically operated by a key.

  ■ a similar device used to prevent the operation of a vehicle or other machine.

• 2 a short section of a canal or river with gates and sluices at each end which can be opened or closed to change the water level, used for raising and lowering boats.

• 3 (also full lock) the maximum extent that the front wheels of a vehicle can be turned.

• 4 (in wrestling and martial arts) a hold that prevents an opponent from moving a limb.

• 5 (also lock forward) Rugby a player in the second row of a scrum.

• 6 (a lock) N. Amer. informal a certainty.

• 7 archaic a mechanism for exploding the charge of a gun.

▶verb

• 1 fasten or be fastened with a lock.

  ■ enclose or secure by locking a door.

  ■ (lock someone up/away) imprison someone.

  ■ (lock someone out) exclude someone.

• 2 make or become rigidly fixed or immovable.

  ■ (lock someone/thing in/into) engage or entangle someone or something in (a struggle or competitive situation).

  ■ (lock on to) locate (a target) by radar or similar means and then track.

• 3 go through a lock on a canal.

– phrases
have a lock on N. Amer. informal have an unbreakable hold on.
lock horns engage in conflict.
lock, stock, and barrel including everything. [referring to the complete mechanism of a firearm.]

– derivatives
lockable adjective,
lockless adjective.

– origin OE loc, of Gmc origin.

Concise Oxford English Dictionary © 2008 Oxford University Press:
lock2

▶noun

• 1 a piece of a person's hair that coils or hangs together.

  ■ (locks) literary a person's hair.

• 2 a tuft of wool or cotton.

– derivatives
-locked adjective.

– origin OE locc, of Gmc origin.