核武器
hé wǔ qì · HSK 7
weapon
☢️💣 核 (nucleus/core) + 武器 (weapon): 武 military + 器 device = nuclear weapon
核 means nucleus or core, the same character used in 核 for atomic-nucleus science. 武器 breaks into 武 (military) plus 器 (device or instrument). Stack them: a core-powered military device, a nuclear weapon.
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).