Synonyms for Filbert (same or very similar meaning)
WordNet sense 1 (small nut-bearing tree much grown in Europe):
cobnut, Corylus avellana, Corylus avellana grandis
WordNet sense 2 (nut of any of several trees of the genus Corylus):
cob, hazelnut
From the ODE community, based on WordNet
add/edit