ear bud vs earplug

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. 

earplug

noun
  • A piece of protective gear meant to be inserted in the ear canal to protect the wearer's hearing from loud noises or the intrusion of water. 

verb
  • To fit with earplugs. 

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