Where to start on answering ‘what is a pound’ The word pound has many definitions. A pound is a unit of measurement in the customary system in the U.S. It is equal to 16 ounces. A pound is also a monetary unit in the UK. It is a place for stray animals and it also means to ‘hammer’, as in ‘he pounded the nail into the board.’ Many ways to use the word ‘pound’. No wonder the English Language can be difficult.