A cèilidh (Scottish Gaelic pronunciation: [ˈkʲʰeːli]) or céilí (Irish pronunciation: [ˈceːlʲiː]) is a traditional Scottish or Irish social gathering. In its most basic form, it simply means a social visit. But in contemporary usage, it usually involves playing Gaelic folk music and dancing, either at a house party or a larger concert at a social hall or other community gathering place.
Cèilidhean (plural of cèilidh) originated in the Gaelic areas of Scotland and Ireland and are consequently common in the Scottish and Irish diasporas. They are similar to the Troyl and Twmpath traditions in Cornwall and Wales, as well as English country dances throughout England where they have in some areas undergone a fusion with céilithe. In Scottish Gaelic it is spelled cèilidh (Scottish Gaelic pronunciation: [ˈkʲʰeːli]), and in Irish it is spelled céilí (Irish pronunciation: [ˈceːlʲiː]).
The term is derived from the Old Irish céle (singular) meaning "companion". It later became céilidhe and céilidh. In Scottish Gaelic reformed spelling it is spelled cèilidh (plural cèilidhean) and in Irish reformed spelling as céilí (plural céilithe).