Where does “grei” come from?

grei (Portuguese) comes from Latin grex, from Proto-Indo-European ger- — to turn, bend, twist, wind; to tie, bind...

grei (Portuguese): small flock of livestock; association; society;...

Definitions

Step	Language	Word	Meaning
1	Latin	grex	a group of smaller animals: a flock of birds, sheep, etc., a pack of dogs, wolves, etc., a swarm of insects, etc
2	Proto-Indo-European	ger-	to turn, bend, twist, wind; to tie, bind...