Proto-Indo-European *reyǵ-

→ English rigid (root)

→ English overreach (root)

→ English reach (root)

→ English reach (derived)

→ English rigorous (root)

→ English rigor (root)

→ Welsh cyfrwy (inherited)

→ Persian فرخسیدن (mention)

→ Irish cuibhrigh (root)

→ Irish cuibhrigh (derived)

→ Latin rigor (root)

→ Latin rigo (derived)

→ Latin rigeo (root)

→ Latin rigeo (derived)

→ Dutch rigide (root)

→ Dutch reiken (root)

→ Dutch rigoureus (root)

→ Old Irish rigid (root)

→ Old Irish rigid (derived)

→ Old Irish conrig (root)

→ Old Irish conrig (derived)

→ Albanian req (inherited)