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lock 1 (lŏk)
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n.
1. A device operated by a key, combination, or keycard and used, as on a door, for holding, closing, or securing.
2. A section of a waterway, such as a canal, closed off with gates, in which vessels in transit are raised or lowered by raising or lowering the water level of that section.
3. A mechanism in a firearm for exploding the charge.
4. An interlocking or entanglement of elements or parts.
5.
a. Sports A hold in wrestling or self-defense that is secured on a part of an opponent's body.
b. A secure hold; control: The distributor has a lock on most of the market.
c. A sure thing; a certainty: His promotion is a lock.
v. locked, lock·ing, locks
v.tr.
1.
a. To fasten the lock of: close and lock a drawer.
b. To shut or make secure with or as if with locks: locked the house.
2. To confine or exclude by or as if by means of a lock: locked the dog in for the night; locked the criminal up in a cell.
3. To fix in place so that movement or escape is impossible; hold fast: The ship was locked in the ice through the winter. She felt that she had become locked into a binding agreement.
4.
a. To sight and follow (a moving target) automatically: locked the enemy fighter in the gun sights.
b. To aim (a weapon or other device) at a moving target so as to follow it automatically: "The pilot had locked his targeting radar on the slow-moving frigate" (Ed Magnuson).
5. To clasp or link firmly; intertwine or interlock: locked arms and walked away.
6. To bind in close struggle or battle: The two dogs were locked in combat.
7.
a. To equip (a waterway) with locks.
b. To pass (a vessel) through a lock.
8. To invest (funds) in such a way that they cannot easily be converted into cash.
9. To arrange or secure (an interest rate) for a loan.
10. Computers
a. To end the processing of (a magnetic tape or disk) in such a way as to deny access to its contents.
b. To protect (a file) from changes or deletion.
v.intr.
1. To become fastened by or as if by means of a lock: The door locks automatically when shut.
2. To become entangled or jammed; interlock.
3. To become rigid or immobile: The mechanism tends to lock in cold weather.
4. To pass through a lock or locks in a waterway.
Phrasal Verbs:
lock down
1. To place (a facility or the people in it) in a lockdown.
2. To arrange or secure (something) so that it does not change or can't be undone.
lock out
To withhold work from (employees) during a labor dispute.
Idioms:
lock horns
To become embroiled in conflict.
lock lips Slang
To engage in a long kiss.
lock, stock, and barrel
To the greatest or most complete extent; wholly: an estate that was auctioned off lock, stock, and barrel.
under lock and key
Securely locked up.

[Middle English lok, from Old English loc, bolt, bar.]

locka·ble adj.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
lock 2 (lŏk)
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n.
1.
a. A length or curl of hair; a tress.
b. often locks The hair of the head.
2. A small wisp or tuft, as of wool or cotton.

[Middle English, lok, from Old English loc, locc.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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