lock

¹ American  

[lok] / lɒk /

noun

1. a device for securing a door, gate, lid, drawer, or the like in position when closed, consisting of a bolt or system of bolts propelled and withdrawn by a mechanism operated by a key, dial, etc.

2. a contrivance for fastening or securing something.

3. (in a firearm)

   1. the mechanism that explodes the charge; gunlock.

   2. safety.

4. any device or part for stopping temporarily the motion of a mechanism.

5. an enclosed chamber in a canal, dam, etc., with gates at each end, for raising or lowering vessels from one level to another by admitting or releasing water.

6. an air lock or decompression chamber.

7. complete and unchallenged control; an unbreakable hold.

   The congresswoman has a lock on the senatorial nomination.

8. Slang. someone or something certain of success; sure thing.

   He's a lock to win the championship.

9. Wrestling. any of various holds, especially a hold secured on the arm, leg, or head.

   leg lock.

10. Horology. (in an escapement) the overlap between a tooth of an escape wheel and the surface of the pallet locking it.

11. Metalworking. a projection or recession in the mating face of a forging die.

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verb (used with object)

locks, present (3rd person singular) locked, past participle, past locking present participle

1. to fasten or secure (a door, window, building, etc.) by the operation of a lock or locks.

2. to shut in a place fastened by a lock or locks, as for security or restraint.

3. to make fast or immovable by or as if by a lock.

   He locked the steering wheel on his car.

4. to make fast or immovable, as by engaging parts.

   to lock the wheels of a wagon.

5. to join or unite firmly by interlinking or intertwining.

   to lock arms.

6. to hold fast in an embrace.

   She was locked in his arms.

7. to move (a ship) by means of a lock or locks, as in a canal (often followed by through, in, out, down, orup ).

8. to furnish with locks, as a canal.

verb (used without object)

locks, present (3rd person singular) locked, past participle, past locking present participle

1. to become locked.

   This door locks with a key.

2. to become fastened, fixed, or interlocked.

   gears that lock into place.

3. to go or pass by means of a lock or locks, as a vessel.

4. to construct locks in waterways.

verb phrase

1. lock out

   1. to keep out by or as if by a lock.

   2. to subject (employees) to a lockout.

2. lock in

   1. to commit unalterably.

      to lock in the nomination of the party's candidates.

   2. (of an investor) to be unable or unwilling to sell or shift securities.

3. lock up

   1. to imprison for a crime.

   2. Printing. to make (type) immovable in a chase by securing the quoins.

   3. to fasten or secure with a lock or locks.

   4. to lock the doors of a house, automobile, etc.

   5. to fasten or fix firmly, as by engaging parts.

4. lock on

   1. to track or follow a target or object automatically by radar or other electronic means.

   2. (in a video game) to target and then maintain the focus of the game camera and the player’s weapon on a selected character or item, though the player character and the targeted character may both be in motion.

5. lock off to enclose (a waterway) with a lock.

idioms

1. lock, stock, and barrel, completely; entirely; including every part, item, or facet, no matter how small or insignificant.

   We bought the whole business, lock, stock, and barrel.

2. lock and load,

   1. to load a gun with ammunition and prepare to fire.

      At twelve years old, I had to lock and load to protect the herd from cattle rustlers.

   2. to ready oneself for action.

      Lock and load, gamers! The tournament starts in ten!

3. lock horns, to come into conflict; clash.

   to lock horns with a political opponent.

4. under lock and key, securely locked up.

   The documents were under lock and key.

lock ² American  

[lok] / lɒk /

noun

1. a tress, curl, or ringlet of hair.

2. locks,

   1. the hair of the head.

   2. short wool of inferior quality, as that obtained in small clumps from the legs.

3. a small tuft or portion of wool, cotton, flax, etc.

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lock ¹ British  

/ lɒk /

noun

1. a device fitted to a gate, door, drawer, lid, etc, to keep it firmly closed and often to prevent access by unauthorized persons

2. a similar device attached to a machine, vehicle, etc, to prevent use by unauthorized persons

   a steering lock

3. 1. a section of a canal or river that may be closed off by gates to control the water level and the raising and lowering of vessels that pass through it

   2. ( as modifier )

      a lock gate

4. the jamming, fastening, or locking together of parts

5. the extent to which a vehicle's front wheels will turn to the right or left

   this car has a good lock

6. a mechanism that detonates the charge of a gun

7. informal a person or thing that is certain to win or to succeed

   she is a lock for the Academy Award

8. completely; entirely

9. any wrestling hold in which a wrestler seizes a part of his opponent's body and twists it or otherwise exerts pressure upon it

10. Also called: lock forward.  rugby either of two players who make up the second line of the scrum and apply weight to the forwards in the front line

11. a gas bubble in a hydraulic system or a liquid bubble in a pneumatic system that stops or interferes with the fluid flow in a pipe, capillary, etc

    an air lock

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verb

1. to fasten (a door, gate, etc) or (of a door, etc) to become fastened with a lock, bolt, etc, so as to prevent entry or exit

2. (tr) to secure (a building) by locking all doors, windows, etc

3. to fix or become fixed together securely or inextricably

4. to become or cause to become rigid or immovable

   the front wheels of the car locked

5. (when tr, often passive) to clasp or entangle (someone or each other) in a struggle or embrace

6. (tr) to furnish (a canal) with locks

7. (tr) to move (a vessel) through a system of locks

8. (esp of two equally matched opponents) to become engaged in argument or battle

9. to take precautions after harm has been done

lock ² British  

/ lɒk /

noun

1. a strand, curl, or cluster of hair

2. a tuft or wisp of wool, cotton, etc

3. literary (plural) hair, esp when curly or fine

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lock More Idioms  

More idioms and phrases containing lock

• under lock and key

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Other Word Forms

Derived Forms

• lockable
  adjective
• lockless
  adjective
• self-locking
  adjective
• well-locked
  adjective

Inflected Forms

Participles

• locking
  present
• locked
  past

Conjugated Forms

Present

• lock
  simple
• locks
  simple
• have locked
  perfect
• has locked
  perfect
• am locking
  progressive
• are locking
  progressive
• is locking
  progressive
• have been locking
  perfect progressive
• has been locking
  perfect progressive

Past

• locked
  simple
• had locked
  perfect
• was locking
  progressive
• were locking
  progressive
• had been locking
  perfect progressive

Future

• will lock
  simple
• will have locked
  perfect
• will be locking
  progressive
• will have been locking
  perfect progressive

Etymology

Origin of lock¹

First recorded before 900; Middle English; Old English loc “fastening, bar”; cognate with Middle Low German lok, Old High German loh, Old Norse lok “a cover, lid,” Gothic -luk in usluk “opening”; akin to Old English lūcan “to shut”

Origin of lock²

before 900; Middle English locke, Old English locc lock of hair, cognate with Old Norse lokkr, Dutch lok curl, German Locke

Explanation

A lock is a tool that keeps a room, house, drawer, or box securely closed. You generally need a key, password, or combination to open a lock. You might use a padlock on your gym locker, opening it with a tiny key or a secret series of numbers. There are also locks called "bolts" like the one on your front door, and bicycle locks that protect your bike while you're at work. Lock also means "to secure with a lock" or "keep securely enclosed," like when you lock your goat in the yard to keep him from eating the neighbor's rose bushes.

Example Sentences

See Examples For:

lock locks locked locking

So before you move to lock in today’s rates for years and years, make sure you feel very good about owning the risks for a long time.

From The Wall Street Journal ● Jul. 14, 2026

He says he decided to lock in the cheaper price at the start of the conflict because he predicted the war would cause prices to rise.

From BBC ● Jul. 14, 2026

"It would also lock Kenya into decades of carbon-intensive development, worsening climate change and its impacts," it said.

From Barron's ● Jul. 14, 2026

Overall, in a volatile market, today is always a better day to lock in a rate.

From MarketWatch ● Jul. 10, 2026

Usually she’d dash into the better bathroom ahead of him, slamming the door shut, jabbing the lock, and shrieking, “Ha, ha, ha! Beat you! You snooze, you lose!”

From "Found" by Margaret Peterson Haddix

If you’ve ever noticed those locks on drugstore shelves, you’ve seen their research at work.

From Slate ● Jul. 13, 2026

The volume of mortgage rate locks rose in June to its highest level in more than three years, signaling a potential pickup in home sales.

From The Wall Street Journal ● Jul. 10, 2026

The typical IPO locks insiders by prohibiting their sales for at least six months.

From Los Angeles Times ● Jul. 1, 2026

The 27-year-old's own voluminous locks will remain intact, having pledged to shave his head if Panama won the World Cup.

From BBC ● Jun. 27, 2026

He had not shorn the bright locks of his hair; they ran rippling down his back.

From "Mythology: Timeless Tales of Gods and Heroes" by Edith Hamilton

China remains locked in a simmering trade feud with the EU, with which it recorded a trade surplus of $32.9 billion in June.

From Barron's ● Jul. 15, 2026

Thai authorities are investigating if negligence was what led to the deadly inferno at a Bangkok bar late on Sunday, as survivors reported doors being locked and the lack of signage demarcating emergency exits.

From BBC ● Jul. 14, 2026

Carbon that does become buried in seafloor sediments, by contrast, can remain locked away for millions of years, accumulating over vast stretches of time.

From Science Daily ● Jul. 12, 2026

The volume of mortgages that people locked in to buy homes rose to its highest level in more than three years in June, according to Optimal Blue, a mortgage technology and data company.

From The Wall Street Journal ● Jul. 10, 2026

They had been adequate enough as long as we were behind locked doors; here they seemed at a loss.

From "The Hiding Place" by Corrie ten Boom

Under normal circumstances, the gravitational interaction between two closely orbiting stars would be expected to synchronize their motion through tidal locking.

From Science Daily ● Jul. 15, 2026

Why parents are locking themselves in cells at Korean 'happiness factory'

From BBC ● Jul. 10, 2026

But if hyperscalers are locking in some pricing now that’s more pegged to current levels, that could limit the rate of pricing growth in 2028, according to Chin.

From MarketWatch ● Jun. 28, 2026

The company announced $20 million in retention awards for both Piepszak and Mary Erdoes, the head of asset and wealth management, which was seen as locking in the two as members of the executive team.

From The Wall Street Journal ● Jun. 26, 2026

For the first several days at dusk, I would ask why we weren't closing the shades, turning down the lights, and locking the doors.

From "March Forward, Girl" by Melba Pattillo Beals

Related Words

• close
• engage
• join
• press
• seal
• shut