- having legal force; properly executed and binding under the law
- well-grounded on principles or evidence; able to withstand criticism or objection, as an argument; sound
- effective, effectual, cogent, etc.
- Archaic robust; strong; healthy
- Logic correctly derived or inferred according to the rules of logic
Origin of validFrench valide from Classical Latin validus, strong, powerful (in ML, valid) from valere, to be strong: see value