Muir’s of all spelling variants are acknowledged to have defended from the Pictish race of Celts, and commonly in both Ireland and Scotland. Many of those spellings can be traced to different locations around the world. These include:

Muir/More/Moore/Mure – Ayshire and areas southwest Scotland
Moar – Orkney and Shetland
Moir – Aherdeenshire and southwest
Mohr – Central lowlands
Mor – Central lowlands
O’More – Ireland
O’Morhda – Ireland
O’Moore – Ireland

The most ancient version of the name is O’Mordha from the word ‘Mordha’, Gaelic for noble, or stately, and the Irish ‘O’More / O’Mordha’ is the current version of this.