Trebbiano (or Ugni Blanc in France) is a white-wine grape originally from Italy, where it generates large quantities of simple but refreshing white wine. The variety has spread northwards from Italy into Europe, most notably France, where it has become the quintessential ingredient in both Cognac and Armagnac.
There are in fact a number of varieties that bear the name Trebbiano, the most common form is Trebbiano Toscano. Trebbiano Toscano is sanctioned for use in about 85 of Italy's 300+ DOCs, but just three DOCGs (confirming its status as a grape of quantity rather than quality). Its most common use is as a blending component, although a handful of DOCs specifically cover single-variety Trebbiano wines. The best known of these is Trebbiano d’Abruzzo.
Other "Trebbiano" grape varieties include Trebbiano Giallo, Trebbiano Modenese, Trebbiano Romagnolo and Trebbiano Spoletino.
The names Trebbiano di Lugana, Trebbiano di Soave and Trebbiano Valtenesi are the same as Verdicchio.