noun

1. a mechanical device furnished with a bolt and, usually, a spring, for fastening a door, strongbox, etc. by means of a key or combination
2. anything that fastens something else and prevents it from opening, turning, etc.
3. a locking together; jam
4. an enclosed part of a canal, waterway, etc. equipped with gates so that the level of the water can be changed to raise or lower boats from one level to another
5. the mechanism of a firearm used to explode the ammunition charge; gunlock
6. air lock (sense )
7. Slang a certainty; sure thing our team is a lock to win the title
8. Wrestling a hold in which a part of the opponent's body is firmly gripped armlock

Etymology: ME < OE loc, a bolt, bar, enclosure, prison, akin to Ger loch, a hole, ON lok, a lid, prob. < IE base *leug-, to bend > Gr lygos, supple twig, L luctȧri, to struggle

transitive verb

1. to fasten (a door, trunk, etc.) by means of a lock
2. to keep from going in or out; shut (up, in or out); confine locked in jail
3. to fit closely; link; intertwine to lock arms
4. to embrace tightly
5. to jam or force together so as to make immovable locked gears, locked brakes
6. to put in a fixed position a throttle locked in the idle position
7. ☆ to equip (a canal, etc.) with a lock or locks
8. to move or pass (a ship) through a lock
9. Printing to fasten (type elements) in a chase or on the bed of a press by means of quoins: often with up

intransitive verb

1. to become locked
2. to be capable of being locked
3. to intertwine or interlock; link together
4. to close tightly and firmly his jaws locked
5. to jam, as gears
6. to pass through the locks of a canal

noun

1. a curl, tress, or ringlet of hair
2. Old Poet. the hair of the head
3. a tuft of wool, cotton, etc.

Etymology: ME lokke < OE loc (akin to Ger locke): basic sense “a bend, twist”: IE base as in lock