ピアノ
ピアノ · piano · JLPT N4 · noun
piano
🎹 ピアノ = pi-a-no, the English word piano borrowed straight into katakana
A loanword (gairaigo), so it is written in katakana: ピ pi + ア a + ノ no. It traces back through English to Italian pianoforte, meaning soft-loud. Say piano with three even beats and you already have the Japanese word.