Definition of musket ball in US English:

musket ball

noun

historical
  • A metal ball of a type used as ammunition in a musket.

Origin

Mid 17th century; earliest use found in James Shirley (bap. 1596, d. 1666), playwright and poet. From musket + ball.

Pronunciation

musket ball

/ˈmʌskɪt bɔːl/