A "Centaur" is when a man is standing proudly while his partner is fellating (performing oral sex) him while on all fours from behind. This position resembles that of a Centaur.
The mainline tank of the Coalition of Ordered Governments (COG) in the Gears of War series by epic games. The Centaur resembles an M4 Sherman on steroids with its treads replaced by four monster truck tires with four wheel steering. It is designed to be fast and rugged.