earplug earplug /ˈiːrˌpləg/

noun

1. A plug of cotton, wax, or rubber that is fitted into the ear canal for protection against the entry of water or loud noise  ( earplug )
   a plug of cotton, wax, or rubber that is fitted into the ear canal for protection against the entry of water or loud noise
    When attending loud concerts, it's advisable to wear earplugs to protect your hearing.
   When attending loud concerts, it's advisable to wear earplugs to protect your hearing.
   
   
2. An earphone that is inserted into the ear canal  ( earplug )
   an earphone that is inserted into the ear canal
    I bought an earplug to listen to music without disturbing others.
   I bought an earplug to listen to music without disturbing others.