(lok) noun
1. A device to fasten an object; specifically, one for so securing a door, drawer, or the like, as to prevent its being opened, except by a special key or combination.
2. A spring mechanism for exploding the charge of a firearm.
3. A section of a canal, etc, enclosed by gates at either end, within which the water level may be varied to raise or lower vessels from one level to another.
4. An intermingling or fastening together; hence, a hold, hug, or grapple in wrestling.
5. A lockup.
6. One of various mechanical devices for fixing something so that it may remain in place.
7. An airlock.
8. A device to prevent a carriage wheel from turning, as in descending a hill.
9. The oblique position of the fore axle with relation to the hind axle of a vehicle when turning or swerving.
—combination lock A lock which can be opened only by combining its dial–operated tumblers in a certain sequence.
—cylinder lock A lock fitted with a cylinder having a control element which can be actuated only by a key whose particularly shaped surface engages with the tumblers and sets them to the exact position for unlocking.
—v.t.
1. To secure or fasten by means of a lock.
2. To shut, confine, or exclude by means of a lock: with in, up, or out.
3. To join or unite securely; interlock; link: to lock arms.
4. To make immovable, as by jamming or by a lock.
5. To provide (a canal, etc.) with a lock or locks.
6. To move (a ship) through a waterway by means of locks.
—v.i.
7. To become locked or fastened.
8. To become joined or linked.
9. To become jammed immovably.
10. To proceed by means of locks: said of ships.
11. To turn (wheels) under a carriage body. [OE loc fastening, enclosure] Synonyms (noun): bar, bolt, catch, clasp, fastening, hasp, hook, latch. A bar is a piece of wood or metal, usually of considerable size, by which an opening is obstructed, a door held fast, etc. A bar may be movable or permanent; a bolt is a movable rod or pin of metal sliding in a socket, and adapted for securing a door or window. A lock is an arrangement by which an enclosed bolt is shot forward or backward by a key, or other device; the bolt is the essential part of the lock. A latch or catch is an accessible fastening designed to be easily movable, and simply to secure against accidental opening of the door, cover, etc. A hasp is a metallic strap that fits over a staple, calculated to be secured by a padlock; a simple hook that fits into a staple is also called a hasp. A clasp is a fastening that can be sprung into place, to draw and hold the parts of some object firmly together, as the clasp of a book.
CYLINDER LOCK
Insertion of the proper key raises all the tumblers (a) to the exact position required to release the key–plug (b), thus permitting the key to turn (here partly inserted).

(lok) noun
1. A tuft of hair; ringlet; tress.
2. plural A head of hair.
3. A small quantity of hay, wool, etc. [OE locc]