Three

Thrash, Thread, Threads, Threat, Threaten, Threatens, Threats, Threefold, Thresh, Threshed, Thresheth, Threshing, Threshold, Threw, Threwest, Thrice, Thrift, Thrill, Thriller, Thrillers, Thrilling, Thrive, Thrives, Thriving, Throat, Throbbing, Thrombus, Throne, Thrones, Throng, Thronged, Thronging, Throttle, Through, Throughly, Throw, Throwing, Thrown, Throws, Thrust, Thruster, Thrusters, Thrusteth