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a door, gate, lid, drawer, or the like in position when closed, consisting of a bolt or system of bolts propelled and withdrawn by a mechanism operated by a key, dial, etc.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

If you are really, really skeptical of the Fed, a few insurance companies even offer income annuities that lock in an annual increase of 5%.

From MarketWatch ● Aug. 31, 2026

Lord Chancellor and Justice Secretary Alex Norris said the government would be "getting spades in the ground quicker to deliver thousands more places to lock up dangerous criminals and keep the public safe".

From BBC ● Aug. 31, 2026

A study of nearly 5,000 schools nationwide that lock student phones in Yondr pouches found them to be an effective way to curb student phone use.

From The Wall Street Journal ● Aug. 29, 2026

Sanitation workers were cleaning the area, cutting down trees, and erecting a new fence and lock to keep out trespassers.

From Los Angeles Times ● Aug. 28, 2026

Suddenly it clicked like a bolt in a lock.

From "Glitch" by Laura Martin

A gate that, as of Wednesday, had two locks on it opens onto a path that leads to the house.

From Los Angeles Times ● Sep. 3, 2026

“It locks in the price that we pay for many of the key components of our business, like storage, as well as compute,” Ramaswamy said.

From MarketWatch ● Sep. 2, 2026

Still, cutting duration locks out future price gains and leaves investors vulnerable to earning lower yields if interest rates fall.

From The Wall Street Journal ● Sep. 1, 2026

One change is an automatic nighttime block that locks teenagers out of Facebook and Instagram between midnight and 6:00 am local time.

From Barron's ● Aug. 26, 2026

His hair was tangled into greasy locks, infested by nits.

From "The Many Assassinations of Samir, the Seller of Dreams" by Daniel Nayeri

Nearly 2 million Americans have been locked out of the market for at least half a year.

From The Wall Street Journal ● Sep. 5, 2026

Bean impressively captures Wanda’s determined grind, but it’s Asante Blackk’s delicate combination of anxiety and ambition as her cousin Lamar, a musical prodigy, that locked me in to the first episode.

From Salon ● Sep. 4, 2026

"The plant isn't running out of evolutionary fuel -- it's increasingly locked into a trajectory that favors pollinator attraction, potentially at the expense of climate adaptation," Baucom said.

From Science Daily ● Sep. 4, 2026

He added that California law requires people carrying handguns into and out of the store to keep them in a locked container and for handguns and long guns to be unloaded.

From Los Angeles Times ● Sep. 4, 2026

If I had been any less shocked, I would have turned around and locked the stall door, but I was petrified.

From "Ida B" by Katherine Hannigan

In 2023, workers accused the company of disrupting union activities, including implying workers could be dismissed for participating in a union protest and locking emergency exits on the day workers planned to picket outside.

From Los Angeles Times ● Aug. 28, 2026

He added: "Some of those habitats are really important at drawing down and locking away carbon."

From BBC ● Aug. 26, 2026

Back to my question: If I sell $1,000 worth of stock now, wouldn’t I essentially be locking in my gains, just like selling during a market downturn would mean locking in my losses?

From MarketWatch ● Aug. 11, 2026

At around 8 p.m., night shift workers shut down every gallery in South Hall, locking every prisoner inside his cell, including the porter, who sometimes acts as an additional set of eyes and ears.

From Slate ● Aug. 11, 2026

Over the next few days, Marx watched Ellsberg locking up again, closing himself off exactly as he had before he’d left for Vietnam.

From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin

Related Words

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