1. electronic equipment that converts sound into electrical signals that can be transmitted over distances and then converts received signals back into sounds;
"I talked to him on the telephone"
2. (phonetics) an individual sound unit of speech without concern as to whether or not it is a phoneme of some language
3. 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"