Symbol

1. tritium-deuterium, a type of hydrogen (H2) molecule

1. Touch Down
2. Tardive Dyskinesia
3. Teachta Dála, a member of Dáil Éireann, the lower chamber of the Parliament of the Republic of Ireland. (See usage notes below in Irish section).

1. (travaux dirigés) practical

1. Teachta Dála, a member of Dáil Éireann, the lower chamber of the Parliament of the Republic of Ireland.

Usage notes

• In English the abbreviation TD is normally used, with TDs as the plural (the full form of which in Irish is Teachtaí Dála).
• The letters follow the name of the member when used as a title, eg, Mr Bertie Ahern TD.