核
hé · HSK 7
pit
🍑 核 = 木 tree + 亥 (sound hài): the hard pit inside fruit, later nucleus/nuclear
Phono-semantic: 木 gives the fruit-seed sense, 亥 carries the sound. The same hard kernel idea stretched from a peach pit to an atomic nucleus, so 核 covers pit, nut, nucleus, and nuclear.
核 — wood 木 + 亥 (phonetic)
A semantic-phonetic compound: 木 ('wood/tree') gives the meaning, while 亥 supplies the sound. It originally referred to a hard-shelled fruit pit or kernel inside wood/fruit, then extended figuratively to 'core,' 'nucleus,' and in modern usage 'nuclear' (as in atomic nucleus).