filbert
A small, round, sweet nut, also called a hazelnut.
A filbert is another name for a hazelnut, the small, round nut that grows on hazel trees. If you've ever eaten Nutella or hazelnut chocolate, you've tasted filberts. They have a sweet, buttery flavor and a smooth brown shell that needs to be cracked open.
Filberts grow in clusters on bushes or small trees, hidden inside leafy green husks that look a bit like tiny wrapped presents. Oregon produces most of America's filberts, where orchards stretch across the Willamette Valley. Squirrels absolutely love filberts and will gather and hide hundreds of them before winter, though they often forget where they buried them, which helps new hazel trees grow.
You'll see both names used: filbert is more common in Oregon and among growers, while hazelnut is what most people call them in stores. Either way, they're the same delicious nut that people have been eating for thousands of years.