The koto — a traditional Japanese stringed instrument (a kind of zither) typically with 13 strings, played with picks or fingers.
子どものころから琴を習っている。
I've been learning the koto since I was a child.
琴の音色が静かな部屋に響いた。
The sound of the koto resonated in the quiet room.
彼女は式典で琴を演奏した。
She performed the koto at the ceremony.
Archaic/general term for stringed instruments — in older texts '琴' could refer to string instruments generally.
古文では『琴』が弦楽器全般を指す場合がある。
In classical literature, '琴' can sometimes refer to stringed instruments in general.
Refers (in some contexts) to Chinese zithers such as the zheng/guzheng — the Chinese plucked zither.
彼女は琴（古筝）を学び、中国音楽の演奏会にも参加している。
She studies the zheng (guzheng) and also participates in Chinese music concerts.
展示室には日本の琴と中国の筝が並べて飾られていた。
In the exhibition room, Japanese koto and Chinese zheng were displayed side by side.