If something’s sanctioned it’s officially approved. Now that your mom has finally come around, watching football with your friends on Sunday is a sanctioned ritual.
When something’s sanctioned, it’s been approved by an authority, like your mom or your school, or it follows established rules or traditions. Eating ham on Easter might be a sanctioned tradition in your family. The word can also be used to say that something has been approved or authorized in a legal sense. You may read about a sanctioned treaty that has been signed by all members of the United Nations.