印证 (yìnzhèng) means 'to confirm or corroborate' — it emphasizes that new information matches or supports existing facts, like evidence backing up a theory. It is more formal and specific than 证明 (zhèngmíng 'to prove'), which is broader and can mean demonstrating something from scratch. Unlike 确认 (quèrèn 'to confirm a fact') or 证实 (zhèngshí 'to verify'), 印证 often implies a mutual fit between two pieces of information.