1The piano, a keyboard instrument in which pressing a key causes a hammer to strike a string and produce sound; widely used from classical to popular music.
子供の頃からピアノを習っている。
I've been taking piano lessons since I was a child.
妹は毎日一時間ピアノを弾く。
My younger sister plays the piano for an hour every day.
コンサートホールのピアノは調律が完璧だった。
The piano in the concert hall was perfectly tuned.
彼はその曲をピアノで即興で弾いた。
He improvised that piece on the piano.
2In music notation, the dynamic marking 'p' (piano), indicating to play softly; the opposite of forte.
この部分はピアノで、優しく弾いてください。
This section is marked piano, so please play it gently.
曲は冒頭がピアノで、終盤はフォルテへと盛り上がっていく。
The piece starts piano (soft) and builds up to forte toward the end.