What is another word for "signet"?

Roget's Thesaurus (1911) lists these synonyms for "signet": accessory, adviser, advocate, agent, agree, agreement, and, assistant, association, attest, attorney, banco, bar, bargain, barrister, barter, beagle, bencher, bond, call, candle, cartel, caveat, charter, civilian, clench, close, come, compact, complete, completion, compromise, conclude, concordat, confirm, consult, contract, convention, conventional, conveyancer.