What does "headphone" mean?

singular of headphones: a cushioned speaker placed on, over, or inside the ear, normally used in left and right pairs.

Headphone

Common synonyms include: earphone, earpiece, acoustical network, calibrated headphone, capacitor speaker, coaxial speaker.

/ˈhɛdfoʊn/ noun

noun ·Uncommon ·Advanced level

Noun

1
singular of headphones: a cushioned speaker placed on, over, or inside the ear, normally used in left and right pairs. form-of, plural-normally, singular
"Some joggers wear only one headphone in their ears, to enjoy music while paying attention to their environment."
2
electro-acoustic transducer for converting electric signals into sounds; it is held over or inserted into the ear wordnet
3
Used with headphones. attributive
"headphone plug"

"Apple's new iPhone doesn't have a headphone jack."

From head + phone.