validyoudaoicibaDictYouDict[valid 词源字典]
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 etymology, valid origin, 英语词源]
valid (adj.)youdaoicibaDictYouDict
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.