来自拉丁语valere, 强健的，勇敢的，词源同value，引申词义有效的。

valid

valid: [16] Something that is valid is etymologically ‘strong’, and hence ‘effective’. The word comes via French valide from Latin validus ‘strong, effective’, which was derived from the verb valēre ‘be strong’ (source also of English valiant, valour, value, etc). The negative form invalid [16] also goes back to Latin, but its specific application to infirm people, differentiated with a distinct pronunciation, was introduced from French in the 17th century.
=> valiant, valour, value

valid (adj.)

1570s, "having force in law, legally binding," from Middle French valide (16c.), from Latin validus "strong, effective, powerful, active," from valere "be strong" (see valiant). The meaning "sufficiently supported by facts or authority, well-grounded" is first recorded 1640s.

1. For foreign holidays you will need a valid passport.

出国度假需持有效护照。

来自柯林斯例句

2. He recognized the valid points that both sides were making.

他认可双方观点中的合理之处。

来自柯林斯例句

3. All tickets are valid for two months.

所有的票在两个月内有效。

来自柯林斯例句

4. He did not accept this reply as valid.

他认为这个回答没有根据。

来自柯林斯例句

5. a bus pass valid for 1 month

公共汽车月票

来自《权威词典》