Neva is a short form of Geneva, which itself could be a short form of Genevieve derived from a medieval name, Genovefa, which is of uncertain origin though it could be derived from Germanic elements kuni (kin, family) and wefa (wife, woman). It might also be derived from Gaulish, composed of Celtic genos (kin, family) with an unknown element.
Geneva is also the name of a city in Switzerland (also spelled Genava in Latin) which might be derived from Celtic genu meaning “bend, knee” or “mouth” referring to an estuary or a bending river.
Neva is also the name of a river that runs from Russia to the Gulf of Finland. The name could be derived from Finnish nevo meaning “sea” though I’ve also seen it listed as coming from Finnish neva meaning “marsh”. Another possible origin is Swedish ny from Old Norse nýr meaning “new”.
As well as being a given name, Neva is also a Finnish surname, referring to someone who lived near a marsh or a bog.
Origin: Germanic, Gaulish, Finnish, Old Norse