Definition: Strong; powerful; efficient.
Definition: Having sufficient strength or force; founded in truth;
capable of being justified, defended, or supported; not weak or
defective; sound; good; efficacious; as, a valid argument; a valid
Definition: Having legal strength or force; executed with the proper
formalities; incapable of being rightfully overthrown or set aside; as,
a valid deed; a valid covenant; a valid instrument of any kind; a valid
claim or title; a valid marriage.