(a) legally effective because made or done with the correct formalities （因符合正当手续）有法律效力的: a valid claim, contract 在法律上有效的要求﹑ 合同 * The marriage was held to be valid. 这一婚姻关系是有效的. (b) legally usable or acceptable （法律上）有效的, 得到认可的: a bus pass valid for one week, for ten journeys 有效期为一周﹑ 为十趟旅程的公共汽车乘车券 * A cheque card is not a valid proof of identity. 银行发的支票保付卡并非有效的身分证明文件. 
(of arguments, reasons, etc) well based or logical; sound （指论据﹑ 理由等）有充分根据的, 符合逻辑的, 确凿的: raise valid objections to a plan 对某项计画提出有力的反对 * Her excuse was not valid. 她的藉口靠不住.> validity / vE5lIdEtI; vE`lIdEtI/ n [U]
1 state of beinglegally acceptable （法律上）有效; 合法（性）: test the validityof a decision 验证某决定是否合法.
2 state of being logical 合逻辑; 正确（性）: question the validity of an argument, assumption 对某一论据﹑ 假定的论点的正确性提出疑问.