'核能' (hé néng) literally combines '核' (hé), meaning 'nucleus' or 'core', and '能' (néng), meaning 'energy' or 'power'. Together, they form the technical term for 'nuclear energy' — the immense energy released during nuclear fission or fusion reactions. This word is used primarily in scientific, environmental, and policy discussions about energy production, safety, and sustainability.

In Chinese, '核能' functions as a formal, uncountable noun and appears in contexts like power generation ('核能发电'), international agreements ('核能安全合作'), and public debates ('发展核能的利与弊'). It carries neutral-to-technical connotations — not inherently positive or negative — though its usage often reflects the speaker's stance on nuclear technology. Unlike colloquial terms like '原子能' (yuánzǐ néng, 'atomic energy'), '核能' is the standard, preferred term in modern official and academic discourse.