The Nykis is a river of Kėdainiai district municipality, Kaunas County, central Lithuania. It is a right tributary of the Liaudė. It originates in Balsiai forest and flows east, meeting the Liaudė in Paberžė village.
There are 3 ponds on the Nykis. Along its course, the river passes Vikaičiai, Margininkai, Graužiai, Miegėnai, Paberžė villages.
The hydronym Nykis possibly derives from the Lithuanian verb nykti ('to disappear, to decay') although it was collated with ('a downstream place'), ('short, low'), Old Slavic ниць ('prostrate') also.
References LIETUVOS RESPUBLIKOS UPIŲ IR TVENKINIŲ KLASIFIKATORIUS (Republic of Lithuania- River and Pond Classifications). Ministry of Environment (Lithuania). Accessed 2011-11-17.