'ball' (plural 'balls') originates from Old Norse and Old English roots: Old Norse 'bollr' and Old English 'beall', ultimately from a Proto-Germanic root *balluz meaning 'round object' or 'ball'.

'ball' changed from Old Norse 'bollr' and Old English 'beall' into Middle English 'ball' and eventually became the modern English 'ball'; senses extended over time to include 'dance' (from Old French 'bal', from Latin 'ballare' to dance) and later slang senses such as 'testicle' and 'courage'.

Initially it meant 'a round object'; over time it retained this core sense while also developing related meanings (a formal dance, slang for 'testicle', and figurative uses like 'courage').