What is gorm?

Some articles on gorm:

Gorman (surname) - Irish Mac Gormáin Family
... According to Keating, the Mac Gormáin family descended from the chieftains of the Uí Bairrche ... the Uí Bairrche), states that after the Mac Gormáin family was driven from its lands a group of them made for Ulster and another made westwards ... The Mac Gormáin family of Ibrickan were known in the 15th century for their wealth, hospitality and their patronage of the Gaelic poets ...