Threat, bygwth, dwrd

Thrice, teirgwaith

Thrive, llwyddo, ffynu, cynnyddu

Throat, corn y gwddf

Throne, gorsedd: gorseddu

Throng, tyrfa: tynlenwi

Thrush, bronfraith

Thrust, gwth: gwthio

Thwart, croes: rhwystro

Tongue, tafod; tafodiaeth