ear bud vs earpiece

ear bud

noun
  • A small earphone designed to be placed in the ear canal for use with portable sound systems. 

  • An immature ear of maize from which the threadlike silks emerge. 

  • An underdeveloped mammalian ear. 

  • A cotton swab. 

earpiece

noun
  • A speaker placed inside or held near to the ear. 

  • The arm on a pair of glasses that hooks over the ear to hold them in place. 

  • A receiver of a telephone to hold near to one's ear. 

How often have the words ear bud and earpiece occurred in a corpus of books? (source: Google Ngram Viewer )