- the thick-shelled, edible nut of certain cultivated varieties of hazel, especially of Corylus avellana, of Europe.
- a tree or shrub bearing such nuts.
- any of several N temperate shrubs of the genus Corylus, esp C. maxima, that have edible rounded brown nuts: family Corylaceae
- Also called: hazelnut, cobnut the nut of any of these shrubs
“hazelnut,” late 14c., from Anglo-French philber (late 13c.), from Norman dialect noix de filbert, in reference to St. Philbert, 7c. Frankish abbot, so called because the hazel nuts ripen near his feast day, Aug. 22 (Old Style). Weekley compares German Lambertsnuss “filbert,” associated with St. Lambert (Sept. 17); also German Johannisbeere “red currant,” associated with St. John’s Day (June 24). The name is Old High German Filu-berht, literally “very bright.”