Several parts combine into one character.

In oracle bone script, 樂 shows 木 (wood) at the bottom with 絲 (silk strings) at the top — a stringed instrument mounted on a wooden frame, like an ancient zither or pipa. From this single image, three meanings unfolded across history: the instrument itself, the music it produces, and the joy that music creates. One character carries instrument → music → pleasure as a single etymological chain. The three CJK regions handle this with three different scripts: traditional 樂 (Korea, Taiwan), Japanese shinjitai 楽 (with 白+幺幺 simplified), Mainland simplified 乐 (a radical contraction).

The most distinctive feature of 樂 is its 破音字 (tone-shifting) behavior — one character read three different ways depending on meaning. In Korean: (ak, music), (rak, pleasure), (yo, to enjoy / love). 音樂 (eumak, music), 苦樂 (gorak, "bitter and pleasant" = ups and downs of life), 快樂 (kwaerak, pleasure), 樂譜 (akbo, sheet music), 樂器 (akgi, musical instrument), and the famous Confucian phrase 樂山樂水 (yosan-yosu, "delighting in mountains and water" — the love of nature).

Mandarin yuè / lè / yào (simplified 乐). yuè = music: 音乐 (yīnyuè, music), 乐器 (yuèqì, instrument), 乐曲 (yuèqǔ, musical composition). lè = happy / pleasure: 快乐 (kuàilè, happy — used in 生日快乐 "happy birthday"), 乐意 (lèyì, willing). yào = to take pleasure in / love: 乐山乐水 (yào shān yào shuǐ). The single character carries an entire emotional and aesthetic vocabulary.

Japanese on-readings split the senses cleanly: ガク (gaku) for music — 音楽 (ongaku, music), 楽器 (gakki, instrument), 楽団 (gakudan, orchestra). ラク (raku) for pleasure / ease — 楽 (raku, comfortable / easy), 楽園 (rakuen, paradise), 快楽 (kairaku, pleasure), 苦楽 (kuraku, pain and pleasure). Kun-reading たのしい (tanoshii, "fun / enjoyable") is among the most frequent adjectives in conversational Japanese — 楽しい時間 (tanoshii jikan, a fun time) is daily speech.

Memory aid: strings on a wooden frame — instrument, music, pleasure, all from one image of ancient music-making.