- the edible nut of a hazel, esp. of a cultivated European tree (Corylus avellana or C. maxima); hazelnut
- a tree bearing this nut
Origin of filbertMiddle English filberde, philliberd, probably via Norman French (noix de) filbert, (nut of) Philibert, after St. Philibert, whose feast came in the nutting season
Earlier filbert-nut, Philibert-nut, from Anglo-Norman noix de filbert, so named because they are ripe near Saint Philibert’s Day.