General English

  • noun a sound made by hitting something
  • verb to hit something

General Science

  • verb to make a loud noise as the mixture of petrol and air in a petrol engine explodes, caused when the mixture is not rich enough in petrol


  • noun a turn at batting by an individual or team; an innings
    Citation ‘They will have to look to compiling well over 400, and very briskly, in their first knock to exert any pressure at all’ (John Sheppard, Sunday Times 8 July 1984)
    Citation ‘Crowe hit eight fours in his attacking knock’ (WCM January 1985)
    Citation ‘Once Sehwag’s breezy knock ended at 36, the Indian innings was becalmed in the face of some accurate bowling’ (Dileep Premachandran, Cricinfo Magazine January 2006)


  • verb to kill. A recent, racier variant of knock off or hit.
  • verb to have sex (with). A 300-year-old usage which has been rare since the early 1960s. It now survives mainly in variations such as knock off, knocked up or knocking shop.
  • verb to criticise, disparage. The use of knock to mean deprecate is no longer, strictly speaking, slang; it has been employed in this sense since the 19th century.
  • verb to cheat. An item of underworld slang.
  • verb to steal. The term is heard particularly in the Scottish Lowlands and the north of England.

Origin & History of “knock”

knock is a classic onomatopoeic word: that is to say, it originated in a direct imitation of the sound it denotes. The similar Swedish knacka ‘knock’ may be related. The figurative use of the word for ‘criticize’ originated in late 19th-century America.