Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “knock”

See all translations

knock

verb uk   /nɒk/ us    /nɑːk/

knock verb (MAKE NOISE)

B1 [I] to repeatedly hit something, producing a noise: She knocked on the window to attract his attention. There's someone knocking on/at the door. Please knock before entering. [I] specialized engineering If an engine is knocking, it is producing a repeated high sound either because the fuel is not burning correctly or because a small part is damaged and is therefore allowing another part to move in ways that it should not. [I] If something such as a pipe knocks, it makes a repeated high sound.
More examples

knock verb (HIT)

B1 [I + adv/prep, T] to hit, especially forcefully, and cause to move or fall: He accidentally knocked the vase off the table. She knocked her head against the wall as she fell. Who knocked over that mug of coffee? [+ obj + adj ] Some thug knocked him unconscious/senseless. She took a hammer and knocked a hole in the wall.knock into each other/knock through If you knock two rooms into each other or knock two rooms through, you remove the wall between them so that they form one room.
More examples

knock verb (CRITICIZE)

[T] UK informal to criticize, especially unfairly: Don't knock him - he's doing his best.

knock

noun [C] uk   /nɒk/ us    /nɑːk/

knock noun [C] (NOISE)

a sudden short noise made when someone or something hits a surface: There was a knock at/on the door.

knock noun [C] (HIT)

the act of something hard hitting a person or thing: He received a nasty knock on the head from a falling slate.
(Definition of knock from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of knock?
Add Cambridge dictionaries to your browser to your website

Definitions of “knock” in other dictionaries

Word of the Day

derivative

If something is derivative, it is not the result of new ideas, but has been developed from or copies something else.

Word of the Day

Lies, lies, lies!

by Kate Woodford,
February 25, 2015
​​​ According to sociologists (=people who study the relationships between people living in groups), we are good at lying. As a species, we have developed a remarkable ability to deceive each other (= persuade each other that something false is true). Being able to say things that are not true can help with

Read More 

snapchat verb

March 02, 2015
to send someone a message using the photomessaging application Snapchat We used to have a thing until he got a girlfriend. now

Read More