‘凭信’ is a formal noun meaning ‘evidence’ or ‘proof’—something tangible or authoritative that confirms the truth or validity of a claim. The first character 凭 (píng) means ‘to rely on’ or ‘based on,’ while the second character 信 (xìn) means ‘trust,’ ‘belief,’ or ‘credibility.’ Together, they convey the idea of something one can reliably base judgment or action upon. It’s commonly used in official, legal, medical, or administrative contexts—not in casual speech.

This term often appears in documents, certificates, or formal statements where verification matters: for example, a doctor’s note serving as ‘medical proof,’ or a notarized document acting as ‘legal evidence.’ Unlike more colloquial terms like 证据 (zhèngjù), 凭信 carries a slightly archaic or bureaucratic tone and implies both authenticity and institutional recognition. It suggests not just raw data but accepted, trustworthy validation.