You may be looking for the French Ardèche, which is pronounced similarly to Ardfheis.
An Ardfheis or Ard Fheis (pronounced[ˈɑːɾˠd̪ˠ ˈɛɕ]; plural Ardfheiseanna) (Irish: Ardfheis) is an annual convention or special convention, usually of a political party. It is an Irish and Scottish Gaelic word, which can be translated loosely as "high festival". The term was first used by Conradh na Gaeilge for its annual convention.
The term is used by most major political parties in the Republic of Ireland, and one major party in Northern Ireland, rather than party conference, to describe their annual party assembly.