Sinn Féin is an Irish republican political party active in both the Republic of Ireland and Northern Ireland. Since forming in 1905, it has worked for the right of self-determination for a united Ireland.
The name Sinn Féin is from the Irish Gaelic expression for “we ourselves”. It’s pronounced Shin Fayn.
The party opposes Westminster’s jurisdiction in Northern Ireland, and its oath to the Queen, so its MPs abstain from sitting in parliament.
[See also: What does Sinn Féin’s victory mean for Northern Ireland’s future?]