1. to remain in a state of being legally or officially acceptable; to continue to be recognized as authentic or legitimate
Your passport will stay valid for another five years.
Seu passaporte permanecerá válido por mais cinco anos.
2. to continue to be relevant, applicable, or true
These arguments stay valid in modern times.
Estes argumentos continuam válidos nos tempos modernos.
3. to maintain effectiveness or usefulness
The warranty will stay valid as long as you follow the instructions.
A garantia permanecerá válida desde que você siga as instruções.