What is a filbert?: Information Roundup
Filbert is merely another name for the hazelnut. Both the Old and the New World shrubs and small trees that produce hazelnuts or filberts belong to the genus Corylus. The nuts are known as filberts particularly when they are grown commercially. Virtually all hazelnuts on the market are called filberts. The origin of filbert is uncertain. The term in various forms dates back in English to the Norman Conquest of 1066 and it occurs in the Middle English of John Gower, [page 27] who died in 1408. The generally accepted theory is that filbert was derived somehow from the proper name Philibert. One conjecture is that it was suggested by the fact that St. Philibert's feast day fell on August 22 in the nutting season About 1612 Henry Peacham who referred to "the Philbert that loves the vale," explained that filbert was "so named of Philbert, a king of France, who caused by arte sundry kinds to be brought forth." In The Tempest (1611) Shakespeare has Caliban promise Stephano he will bring him "to clustering filberts." Some authorities derive the term from Old High German Filu-berht, literally "very bright." Still others suppose that fillbeard was the original form and that the nut was so called because it just fills up the cup formed by the beards of the calyx. The Romans called the hazelnut or filbert avellana, from Avella (Abella), a city in the province of Campania, Italy, where the nuts were produced in large quantities in ancient times. Corylus avellana is the scientific name of a species of filbert widely cultivated in Europe. In The Bible in Spain (1849) George Borrow wrote that the town of Valliviciosa near Oviedo in northern Spain "is sometimes called La Capital de las Avellanas, or the capital of the Filberts, from the immense quantity of this fruit which is grown in the neighborhood; and the greatest part of which is exported to England."