Litavis—also known as Litauis, Litaui, Litauia, and Llydaw—is a goddess in Celtic mythology worshiped by the ancient Gauls. Her name is found in inscriptions found at Aignay-le-Duc and Mâlain of the Côte-d'Or, France, where she is invoked along with the Gallo-Roman god Mars Cicolluis in a context which suggests that she might have been his consort. Also, a Latin dedicatory inscription from Narbonne (which was in the far south of Gaul), France, bears the words “MARTI CICOLLUI ET LITAVI” ("To Mars Cicolluis and Litavis").
Letavia or Letauia may be derived from a Proto-Indo-European root *peltHa- "to spread out flat", via a zero-grade, suffixed formation, *PltHa-wiH, meaning "The Broad One". The name may thus be comparable to the Vedic earth goddess “Prthvi” and the Greek place name Plataia, suggesting that Letavis is an earth goddess or divinisation of the landscape.
Brittany is standardly referred to as Llydaw in Modern Welsh, echoing the use of the name Letavia for Brittany (or part of it) In Latin texts. The Chronicle of Robert de Torigni states of the peninsular, quae antiquitus letauia sive armorica uocata est (“which was anciently called Letavia or Armorica”). Likewise, the Life of Saint Goulven refers to partes letaniae quae pars est armoricae siue britanniae minoris ("the regions of Letania, which is a part of Armorica or Little Britain"). This latter passage displays the common confusion of the letter n with u or v in medieval manuscripts. "Letavia" may be derived from "Litavis", so the place-name would mean "Land of Litavis".