Signet comes from Old French signet ('small seal'), diminutive of signe ('sign'), from Latin signum ('mark, sign'). The historical chain includes Old French signet and Latin signum. The quoted older senses, "small seal", "sign", and "mark, sign", supply the semantic anchors for signet. The formation is best read as borrowed: the word signet carries its older form-history into a compact English lexical shape. In present English it is used as a noun, "a small seal, often set in a ring, used to authenticate documents". Related English forms include sign, signature, signatory, and sigil. The result is a noun whose etymology preserves both the older form and the later English specialization.