What is the thicker form of spaghetti called?

The thicker form of spaghetti is called spaghettoni.

Spaghettoni is a long, solid, cylindrical pasta whose diameter is greater than standard spaghetti. The name uses the Italian augmentative ending “-oni,” which broadly conveys the idea of something larger or thicker. By contrast, spaghettini is thinner, while capellini is thinner still.

These varieties are closely related, so the names are easy to mix up. Bucatini is also relatively thick, but it has a hollow center; that tube-like structure makes it a different pasta shape. Spaghettoni remains solid like ordinary spaghetti.

Because its larger diameter takes longer to cook, spaghettoni is often paired with substantial sauces that cling to its surface. Like other dried pasta, it is commonly made from durum-wheat semolina and water, then extruded through a die and dried.