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Idioms about knock

Origin of knock

First recorded before 1000; 1890–95 for def. 4; Middle English knokken, knoken (verb), Old English cnocian, cnucian; cognate with Old Norse knoka “to thump, knock”

synonym study for knock

1. See strike.


knockless, adjectivere·knock, verbun·knocked, adjectiveun·knock·ing, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What is a basic definition of knock?

Knock is a verb that means to hit something by bumping into it. Knock also means to repeatedly strike something to make a noise. Knock is used as a noun to mean a sound made by repeated tapping. Knock has many other senses as a verb and a noun. It is also used in several idioms.

Knock means to strike something by bumping into it or colliding with it. This sense of knock is often followed by what was bumped into  (knocked onto the floor).

  • Real-life examples: In bowling, the goal is to knock down all of the pins with a bowling ball. In boxing, the competitors repeatedly knock each other in the head and body with their fists. It is difficult to build a house of cards without accidentally knocking it over.
  • Used in a sentence: Shawna wasn’t paying attention and accidentally knocked over a stack of boxes. 

When you knock on a door, you hit it with your knuckles, fist, or an object, like a door knocker, usually repeatedly. You might knock on a door or window to get someone’s attention or to signal to them that you want to be let inside (or out!).

  • Used in a sentence: He knocked on the wall with his umbrella to get everyone’s attention. 

In a related sense, a knock is the noise you make when you hit something, like a door or window, to get someone’s attention.

  • Used in a sentence: I think you have a visitor because I heard a knock at the door. 

The word knock is used in several idioms. For example, if someone “knocks your socks off,” it means they have a positive, overwhelming effect on you.

Where does knock come from?

The first records of knock come before the year 1000. It comes from the Old English cnocian and is related to the Old Norse verb knoka, meaning “to thump.”

Did you know ... ?

What are some other forms related to knock?

  • knocker (noun)
  • knockless (adjective)
  • reknock (verb)
  • unknocked (adjective)
  • unknocking (adjective)

What are some synonyms for knock?

What are some words that share a root or word element with knock?

What are some words that often get used in discussing knock?

How is knock used in real life?

Knock is a common word that often means to tap something with your knuckles or to bump into something.

Try using knock!

Is knock used correctly in the following sentence?

The cat knocked the pitcher off the table, and it smashed against the floor.

How to use knock in a sentence

British Dictionary definitions for knock

/ (nɒk) /


Word Origin for knock

Old English cnocian, of imitative origin; related to Old Norse knoka to hit
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with knock


The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.