earphone has definitions from the field of physics
1
[ noun ] (physics) electro-acoustic transducer for converting electric signals into sounds; it is held over or inserted into the ear

Examples

"it was not the typing but the earphones that she disliked"

Used in print

(Donald J. Plantz, Sweeney Squadron....)

His earphones were constantly full of the sounds of enemy contacts made by other flights .

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