考证 (kǎo zhèng) is a formal verb meaning 'to verify' or 'to authenticate'—especially facts, historical claims, sources, or textual accuracy. The first character 考 (kǎo) means 'to examine, investigate, or test', and the second 证 (zhèng) means 'evidence' or 'proof'; together, they literally convey 'examining evidence'. This word is commonly used in academic, historical, journalistic, and scholarly contexts where rigorous checking of information is required.

It often appears in written Chinese rather than casual speech, especially in research papers, editorial notes, or discussions about authenticity (e.g., verifying ancient texts, medical claims, or historical records). While it can be used transitively ('verify something'), it frequently occurs with objects like 史实 (historical facts), 文献 (documents), or 说法 (claims). It implies methodical, evidence-based scrutiny—not just casual confirmation.