The story
- Proto-Indo-European*Hreyǵ-
- Proto-Italic*rigēō
- Latinrigeō
- Proto-Indo-European*dʰeh₁-
- Latinrigidus
- Middle Englishrigide
- English todayrigid
From Middle English rigide, from Latin rigidus (“stiff”), from rigeō (“to be stiff”). Compare rigor. Merged with Middle English rigged, rygged, rugged (“upright like a spine, rigid”, literally “ridged”).
Words from the same roots
Middle Englishrigged all →
ridged
Etymology from Wiktionary, CC BY-SA 4.0.