What is "midir"

In the Mythological Cycle of early Irish literature, Midir ( Old Irish) or Midhir ( Modern Irish) was a son of the Dagda of the Tuatha Dé Danann. After the Tuatha Dé were defeated by the Milesians, he lived in the sidh of Brí Léith (believed to be Ardagh Mountain, Co. Longford). In the First Recension of the Lebor Gabála, Midir of Brí Léith is made the "son of Induí son of Échtach son of Etarlam".