third-degree I. \| ̷ ̷ ̷ ̷| ̷ ̷\adjective Etymology: from the phrase third degree : of a degree next to the second; specifically: of a degree of criminal culpability or seriousness second after first-degree < third-degree arson > II. transitive verb Etymology:third degree : to administer the third degree to < the police beat prisoners and third-degree them — Newsweek >