From *leit- (related to Latin lītus < *leitos), from Proto-Baltic *lei-, *lie- with an extra -t, from Proto-Indo-European *ley-, *lī- (“to pour, to flow, to drip”). The stem was perhaps originally a reference to people from the "land of the rain" or "land of the rivers." It is also possible that there was an original river or lake name *Leitā, from which *leitā-tyā, *leityā > leiša, from which the nominative leitis could be derived.
leitis m (2nd declension, feminine form: leitiete)
- a (male) Lithuanian
- strādnieki... kalpi, vai tie būtu vācieši, leiši, krievi, ebreji, mums draugi — workers... servants, be they Germans, Lithuanians, Russians, Jews, are friends to us
- (genitive plural): Lithuanian, pertaining to Lithuania and its people
- leišu valoda — the Lithuanian language
- Aspazija pieraksta leišu sakāmvardus un mīklas — Aspazija recorded Lithuanian proverbs and riddles
- ^ “lietuvieši” in Konstantīns Karulis (1992, 2001), Latviešu Etimoloģijas Vārdnīca, in 2 vols, Rīga: AVOTS, ISBN: 9984-700-12-7