learning by ear; picking up by listening
Refers to acquiring knowledge or a skill through listening rather than formal study. Often used in contexts like language learning or memorizing music.
He learned to play guitar by ear.
having heard before; sounding familiar
Almost always used in the phrase 聞き覚えがある to mean something sounds familiar or one has heard it before.
See also: 聞き覚えがある
That voice sounds familiar.
I feel like I've heard this song somewhere before.