Cách sử dụng
The expression "brass monkeys" is used to mean that it is very cold outside. The phrase comes from the British Navy where during extremely cold weather, the cannons and cannonballs, which were made of iron and brass, would get so cold that they would contract and the cannonballs would fall off the racks. This would cause the balls to form piles that looked like "brass monkeys". So, if someone says, "It's brass monkeys outside", it means that it is really cold out!