valid
/ˈvælɪd/·밸리드·adjective
legally or logically acceptable
LatinCEFR B1
Root
Latin 'validus' (strong)
Latin validus → Middle French valide → English valid (16th c.)
In a word
Latin validus = 'strong'. The val root (worthy, strong) meets -id (adjective form) and becomes valid. In English, "valid" means "still standing, still in force." A valid ticket is one that hasn't collapsed yet. Expiration date = the moment that sturdiness gives way.
Examples
Your ticket is valid for one month.
She made a valid point in the debate.
The data are valid and reproducible.
Related
valueevaluateinvalidvalidateavailable