What is "deo-ghreine"

Deò-ghrèine or Deò-grèine meaning “ray of sunshine” can refer to the following:

1. Fionn mac Cumhaill's famous banner, also known as “Deò-ghrèine Mhic Cumhail” after him.
2. Perhaps inspired by MacCumhail's banner, An Deò-gréine was also used as the name of a Scottish Gaelic magazine, the organ of An Comunn Gàidhealach, first produced in 1905, later being retitled An Gàidheal. Its editors included Malcolm Macfarlane (1905-6) and Rev. Malcolm MacLennan (1906-8), best known for his dictionary.
3. In James MacPherson’s Ossianic stories, based on Gaelic mythology, but with his own additions, it was also used for “the daughter of Cairbre, and wife of that Cruthgheal who was slain in battle by Swaran, king of Scandinavia [Lochlin]” Some say that this character originally represented a daughter of the sun, something common in various mythologies. She was held captive in the Land of the Big Women, freed by Cailleach (disguised as a fox) and Brian.