1. declare or make legally valid

Similar word(s): formalise, formalize

Definition categories: social, authorise, authorize, clear, pass

2. prove valid; show or confirm the validity of something

Definition categories: cognition, affirm, confirm, corroborate, substantiate, support, sustain

3. give evidence for

Similar word(s): corroborate

Definition categories: communication, confirm, reassert

4. make valid or confirm the validity of

- validate a ticket

Definition categories: change, alter, modify