Definition of brass monkey in English:

brass monkey

Syllabification: brass mon·key

noun

informal
Used in phrases to refer to extremely cold weather: it’s brass monkey weather tonight
More example sentences
  • Similarly, pack your thermals, because it's colder than a brass monkey's ice lolly.
  • Actually the weather today is much milder than yesterday when it was cold enough to freeze the spheres off a brass monkey (an old sea-faring expression).
  • It got cold on the gun decks and the indentations in the brass monkey would get smaller than the iron cannonballs they were holding.

Origin

mid 19th century: often said to be from a type of brass rack or 'monkey' in which cannonballs were stored and which contracted in very cold weather, ejecting the balls, but this explanation has not been proved.

Definition of brass monkey in: