1To produce sound on stringed or keyboard instruments (e.g. piano, guitar) by using hands or fingers; to play (an instrument).
彼女は毎朝ピアノを弾いてから学校へ行く。
She plays the piano every morning before going to school.
休みの日に友だちとギターを弾いて歌った。
On my day off I played guitar and sang with friends.
この曲は指で優しく弾くときれいに聞こえる。
This piece sounds beautiful when gently plucked/played with the fingers.