valid

UK: /ˈvælɪd/ US: /ˈvælɪd/ ,(val′id)

WordReference Random House Learner's Dictionary of American English © 2026

val•id /ˈvælɪd/   adj. 

1. sound; just;
   well-founded:
   a valid argument.
2. having proper authority;
   that can be used legally or properly;
   authoritative:
   a valid driver's license.
3. legally sound, effective, or binding:
   a valid contract.

va•lid•i•ty /vəˈlɪdɪti/  n. [uncountable]
val•id•ness, n. [uncountable] See -val-.

WordReference Random House Unabridged Dictionary of American English © 2026

val•id  (val′id), adj. 

1. sound;
   just;
   well-founded:
   a valid reason.
2. producing the desired result;
   effective:
   a valid antidote for gloom.
3. having force, weight, or cogency;
   authoritative.
4. legally sound, effective, or binding;
   having legal force:
   a valid contract.
5. Philosophy [Logic.] (of an argument) so constructed that if the premises are jointly asserted, the conclusion cannot be denied without contradiction.
6. [Archaic.] robust;
   well;
   healthy.

• Latin validus strong, equivalent. to val(ēre) to be strong + -idus -id⁴
• 1565–75

val′id•ly, adv. 
val′id•ness, n. 
Synonyms

• 3. substantial, cogent.
• 5. logical, convincing.

Collins Concise English Dictionary © HarperCollins Publishers::

valid / ˈvælɪd/ adjective

1. having some foundation; based on truth
2. legally acceptable: a valid licence
3. having legal force; effective
4. having legal authority; binding
5. having some force or cogency: a valid point in a debate
6. (of an inference or argument) having premises and conclusion so related that whenever the former are true the latter must also be true, esp (formally valid) when the inference is justified by the form of the premises and conclusion alone. Thus Tom is a bachelor; therefore Tom is unmarried is valid but not formally so, while today is hot and dry; therefore today is hot is formally valid
   Compare invalid22
7. healthy or strong

Etymology: 16th Century: from Latin validus robust, from valēre to be strong

validity / vəˈlɪdɪtɪ/, ˈvalidness noun

ˈvalidly adverb