earpiece(n = noun.artifact) earphone, headphone, phone - electro-acoustic transducer for converting electric signals into sounds; it is held over or inserted into the ear; "it was not the typing but the earphones that she disliked"
a device for converting electric signals into sounds, designed to be held over or inserted into the ear; as, The common telephone handset has a speaker and an earpiece. [WordNet 1.5]