Where does “ateis” come from?

ateis (Lithuanian) comes from Lithuanian ateiti, from Lithuanian eiti, from Proto-Balto-Slavic eitei, from Proto-Indo-European h₁éyti, from Proto-Indo-European h₁ey- — to go.

ateis (Lithuanian): third-person singular future of ateiti;...

Definitions

third-person singular future of ateiti;...

Ancestry of “ateis”, step by step

Step	Language	Word	Meaning
1	Lithuanian	ateiti	to come, to arrive
2	Lithuanian	eiti	to go; to walk
3	Proto-Balto-Slavic	eitei	to go
4	Proto-Indo-European	h₁éyti	to go, to be going
5	Proto-Indo-European	h₁ey-	to go

Every word from Proto-Indo-European h₁ey- →Every word from Proto-Indo-European h₁éyti →Every word from Proto-Balto-Slavic eitei →