Invalid may refer to:
- Patient, a sick person
- one who is confined to home or bed because of illness, disability or injury (sometimes considered a politically incorrect term)
- .invalid, a top-level Internet domain not intended for real use
As the opposite of valid:
- Validity, in logic, true premises cannot lead to a false conclusion
- Validity (statistics), a measure which is measuring what it is supposed to measure
See also[edit]
- All pages with titles beginning with Invalid
- All pages with titles containing Invalid
- Void (disambiguation)