Its source is a Gaelic expression meaning "Grain."
Gráinne may derive from the name of an ancient Celtic corn goddess. Alternate interpretations include ''revulsion'' and ''terror.''
A character with this name was loved by Finn MacCool, legendary leader of the ancient Fenians. She tried to run away with the hero's nephew, but Finn pursued them and killed her lover. True to the tradition of Irish romance, she put an end to herself.
Gráinne Ni Maille (known also as Grace O'Malley) was a seagoing warrior who opposed and intrigued with the English in the late 16th century. A commander of sizable pirate fleets, she was captured a number of times, and at least once barely escaped hanging. Though pardoned by Queen Elizabeth, she was unwilling to give up her freebooting ways, and pursued her violent career to the end of her life.