签约 literally means 'to sign (qiān) a contract or agreement (yuē)'. It is a compound verb formed by combining the action of signing with the object — a formal, binding document outlining mutual obligations. The character 签 carries the sense of affixing one’s signature as official confirmation, while 约 refers specifically to a written agreement, pact, or covenant — not just any promise, but one with legal or professional weight.

This term is commonly used in business, employment, real estate, and entertainment contexts — for example, when an athlete joins a team, a writer signs with a publisher, or a tenant finalizes a lease. It implies completion of negotiations and entry into a formal relationship. While often used transitively (e.g., 签约公司), it can also appear in passive or resultative constructions (e.g., 已签约, 成功签约). It’s more formal than everyday verbs like 签字 ('to sign one’s name') and carries stronger implications of commitment and enforceability.