- TWM O'R NANT - gweler EDWARDS, THOMAS
- TWM PEDROG - gweler WILLIAMS, THOMAS
- TWM SBAEN - gweler JONES, THOMAS
- TWM SHÔN CATI - gweler JONES, THOMAS
- TWM SIÔN CATI - gweler JONES, THOMAS
- TYDDEWI, Is-iarll 1af - gweler PHILIPPS, JOHN WYNFORD
- TYDECHO (fl. 6ed ganrif), sant Celtig
- TYDFYLYN - gweler WILLIAMS, DANIEL THOMAS
- TYSILIO (fl. 7fed ganrif), sant Celtig