filbert

UK: /ˈfɪlbət/ US: (fil′bərt)

WordReference Random House Unabridged Dictionary of American English © 2025

fil•bert  (fil′bərt), n. 

1. Plant Biology the thick-shelled, edible nut of certain cultivated varieties of hazel, esp. of Corylus avellana, of Europe.
2. Plant Biology a tree or shrub bearing such nuts.

• Middle English, short for filbert nut, so called because ripe by Aug. 22 (St. Philbert's day) 1250–1300

Collins Concise English Dictionary © HarperCollins Publishers::

filbert / ˈfɪlbət/ noun

1. any of several N temperate shrubs of the genus Corylus, esp C. maxima, that have edible rounded brown nuts: family Corylaceae
2. Also called: hazelnut, cobnut the nut of any of these shrubs

See also hazel1, Etymology: 14th Century: named after St Philbert, 7th-century Frankish abbot, because the nuts are ripe around his feast day, Aug 22