noun

1. the act of a recognized authority confirming or ratifying an action; authorized approval or permission
2. support; encouragement; approval
3. something that gives binding force to a law, or secures obedience to it, as the penalty for breaking it, or a reward for carrying it out
4. something, as a moral principle or influence, that makes a rule of conduct, a law, etc. binding
5. : often used in pl.
   1. a coercive measure, as a blockade of shipping, usually taken by several nations together, for forcing a nation considered to have violated international law to end the violation
   2. a coercive measure, as a boycott, taken by a group to enforce demands
6. Obsolete a formal decree; law

Etymology: < Fr or L: Fr < L sanctio < sanctus: see saint

transitive verb