Glas Gaibhnenn

Glas Gaibhnenn (Irish: Glas Gaibhnenn, Glas Ghaibhleann; Hiberno-English: Glas Gaivlen; Gloss Gavlen: pronunciation guide:/glas-gav-e-lan/;), in Irish folklore, is a prized fabulous cow of bounty (fertility) that yields profuse quantities of milk.

The cow is owned variously by a smith who may be named Gaivnin (hence reinforcing the notion that the cow's name is eponymous after him) or by the hero Cian mac Cáinte (sometimes called Mac Kineely), equivalent to Cian father of Lugh of mythology. The cow is stolen (or craftily regained) by Balar or Balor the strong-smiter. The hero, in order to fulfill the quest to recover the cow, is transported by a banshee to a tower where Balor's daughter is sequestered, to produce a child destined to kill Balor.