Gaelic
Presumably Ireland or Scotland.
Ireland is the English language equivalent of Eire. Eire is the Irish name for the island of Ireland. Its not the only name used in the Irish language others such as Banbha were used. Eire was a princess of the Tuatha de Danaan the semi-mythical early Celts who assumed god-like charachteristcs. Ireland is named after her.
That was Ireland. Scotland was Caledonia
There is no special name for Northern Ireland and Scotland together.
The republic of Ireland has two official languages. In Irish, the official name of the country is "Éire". In English the official name is "Ireland". We call ourselves 'Irish' in English and 'Éireannaigh' in Irish. Historically, the early people who lived here are recorded as being the Celts, but there is little evidence that any of us are pure Celts nowadays - there's been a lot of Vikings, Normans, and English here since then. Poetically and in the Irish language the people were referred to as Gaels.
Ireland and Scotland
Scotland and Ireland.
Although many outside of Ireland refer to the native language as "Gaelic", in Ireland itself it is called "Irish"; the related language of Scotland is simply called "Gaelic" in that country. Irish is called Gaeilge and (Scots) Gaelic is calledGàidhlig in their respective languages.The term Gaelic can also refer to the common culture of Ireland, Scotland and the Isle of Man; as in "Gaelic football".
Ireland gets its name from Éiru - a goddess and member of a (possibly) mythological race who inhabited Ireland before the Celts - the Tuatha de Danann.
Ireland's real name is Éire, which is in the Irish language and which in English is Ireland.
Because it was ruled by Scots (from Ireland!)
The United Kingdom is the collective name for England, Scotland, Wales, and Northern Ireland. The full name of the UK is the "United Kingdom of Great Britain and Northern Ireland", because Great Britain is the name for England, Scotland, and Wales.