pom-pom
noun
[ ˈpɒmpɒm ]
• a small woollen ball attached to a garment, especially a hat, for decoration.
Origin:
mid 18th century (originally denoting a bunch of ribbons, feathers, etc. worn by women in the hair or on a dress): French pompon, of unknown origin.
pom-pom
noun
• an automatic quick-firing two-pounder cannon of the Second World War period, typically mounted on a ship and used against aircraft.
Origin:
late 19th century: imitative of the sound of the discharge.