Origin: Greek suffix -phone
Headphone has 2 different meanings across 1 category:
A listening device placed or worn in the ear, usually sold in pairs
"She plugged her new headphones into the player to listen to her favorite songs privately."
In plain English: Headphones are earpieces you wear over your ears to listen to music without making noise for people around you.
"I put my headphones on to listen to music while I walk home."
Usage: Use "headphones" as the plural form when referring to the pair of devices; avoid treating the singular "headphone" as a countable noun unless specifying a single unit. The term is standard in both casual conversation and technical contexts without needing special register adjustments.
The word headphone is a straightforward combination of the words head and phone that was first used to describe an audio device worn on the ears. It entered English by merging these two common terms to create a new compound noun for this specific technology.