/'vælɪd; `vælɪd/
adj
1 (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.
2 (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.

adj
[Date: 1500-1600; Language: French;Origin: valide, from Latin validus 'strong, effective', from valere; VALOR]
a valid ticket, document, or agreement is legally or officially acceptable
≠ invalid
　a valid credit card
　Your return ticket is valid for three months.
valid reason/argument/criticism etc
a reason, argument etc that is based on what is reasonable or sensible
　Police officers must have a valid reason for stopping motorists.
a valid password, ID etc is one that will be accepted by a computer system
≠ invalid
>validity [və'lɪdɪti/