Veto/ˈviːtəʊ/ Definition 1 of 4Pro Tip 1/2Government Authority Veto as a noun often relates to official governmental powers and is considered a formal term. The mayor's veto prevented the new parking ordinance. Pro Tip 2/2Rare Personal Use While veto originates from government use, it can be used personally to humorously show strong opposition. Mom put a veto on junk food in our house.