Celt a member of a group of peoples inhabiting much of Europe and Asia Minor in pre-Roman times. Their culture developed in the late Bronze Age around the upper Danube, and reached its height in the La Tène culture (5th to 1st centuries bc) before being overrun by the Romans and various Germanic peoples. The language group of the Celts is Celtic, constituting a branch of the Indo-European family and including Irish, Scottish Gaelic, Welsh, Breton, Manx, Cornish, and several extinct pre-Roman languages such as Gaulish.
Celtic Church the Christian Church in the British Isles from its foundation in the 2nd or 3rd century until its assimilation into the Roman Catholic Church (664 in England; 12th century in Wales, Scotland, and Ireland).
Celtic cross a Latin cross with a circle round the centre.
Celtic fringe the Highland Scots, Irish, Welsh, and Cornish in relation to the rest of Britain; the term, often regarded as derogatory, is recorded from the late 19th century.
Celtic tiger the Irish economy seen as a successor to the earlier tiger economies.
Celtic twilight the romantic fairy tale atmosphere of Irish folklore and literature; the term derives originally from W. B. Yeats's name for his collection of writings (1893) based on Irish folk-tales.

Celt Someone who speaks one of the Celtic languages or is descended from a Celtic language area. After 2000 bc, early Celts spread from e France and w Germany over much of w Europe, including Britain. They developed a village-based, heirarchical society headed by nobles and Druids. Conquered by the Romans, the Celts were pushed into Ireland, Wales, Cornwall, and Brittany by Germanic peoples. Their culture remained vigorous, and Celtic churches were important in the early spread of Christianity in n Europe.

Celt / kelt; selt/ • n. a member of a group of peoples inhabiting much of Europe and Asia Minor in pre-Roman times. Their culture developed in the late Bronze Age and reached its height in the 5th to 1st centuries bc before being overrun by the Romans and various Germanic peoples. ∎  a native of any of the modern nations or regions in which Celtic languages are (or were until recently) spoken; a person of Irish, Highland Scottish, Manx, Welsh, or Cornish descent.

celt prehistoric instrument with chisel edge. XVIII. — modL. celtes, based on celte, which occurs in the Clementine text of Vulg., Job 19: 24 (‘stylo ferreo et plumbi lamina vel celte sculpantur in silice’), where some MSS. read certe ‘surely’ (corr. to ‘for ever’ of A. V.); the adoption of the word as a techn. term of archaeology was prob. assisted by a supposed connection with Celt.

Celt, Kelt †a Gaul XVII; one who speaks a Celtic language XVIII. In the earliest use — L. Celtæ pl. — Gr. Keltoí; in the mod. use — F. Celte.
So Celtic XVII. — L. Celticus and F. celtique.