reig- / Indo-European roots
To reach, stretch out.Oldest form *reig̑-, becoming *reig- in centum languages.
1. O-grade form *roig-. reach from Old English rǣcan, to stretch out, reach, from Germanic *raikjan.
2. Possibly suffixed (stative) zero-grade form *rig-ē-. rigid, rigor from Latin rigēre, to be stiff (? < "be stretched out").
[Pokorny (reig̑-) 862.]