(1)相互关系；共同关系；连续关系
即法律关系，指在契约当事人、遗嘱执行人与立遗嘱人、财产转让人与受让人、继承人与被继承人、主债务人与担保人等法律关系当事人之间存在的对同一财产权利的相互关系、共同关系或连续关系。

(2)私下知悉；知情；暗中参与

• subject to
• subject to contract
• subject to final payment
• subject to restriction
• sub judice
• sub jugum matrimonii
• Sublata veneratione majistratuum; respublica ruit.
• Sublato fundamento, cadit opus.
• Sublato principali, tollitur adjunctum.
• sublease
• sublessee
• sublessor
• subletting
• submerged fen
• submerged lands
• Submerged Lands Act
• submergence
• submersible apparatus
• submission
• submission agreement
• submission bond
• submission of controversy
• submission to arbitration
• submission to jury
• submission to nonsuit