1. diel - Adjective
2. Diel - Proper noun
diel (not comparable)
(biology) Having a 24-hour period regardless of day or night.
Diel (plural Diels)
A surname.
Advice from Marshall, Diel & Myers on the importance of creating a living will. Source: Internet
Seasonal and diel patterns of grizzly bear diet and activity in west-central Alberta. Source: Internet
Importance of diel behaviour when studying habitat selection: examples from female Scandinavian brown bears (Ursus arctos). Source: Internet