核能
hé néng · HSK 7
nuclear energy
⚛️ 核能 = 核 (nucleus/core) + 能 (energy) = nuclear energy
核 means nucleus or kernel (as in 核桃, walnut); 能 means energy or ability. Put the core and the power together and you get the energy released from an atom's nucleus.
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).
能 — 厶 (head) + 月 (body/flesh) + 匕匕 (legs)
Originally a pictograph of a bear, showing its head, body, and powerful legs. Because bears were seen as strong and capable, the character was borrowed to mean 'ability' or 'can'. A new character 熊 (with the fire radical 灬) was later created for 'bear'.