ěr​sāi

earplug

耳塞 ěr​sāi
earplug noun
a piece of material inserted into the ear canal to protect against noise or water

He wore earplugs to sleep on the plane to block out the noise.

earphone noun
a small electronic device worn in or over the ear to listen to audio

The sound quality of this pair of earbuds is excellent.

Frequency

Movie subtitles
1.49 per million appears in 1% of films
Written text
1.48 per million

Sources

Definitions
CC-CEDICT