Spaghetti is a long, thin, solid, cylindrical pasta. It is a staple food of traditional Italian cuisine. Like other pasta, spaghetti is made of milled wheat and water and is sometimes enriched with vitamins and minerals. Italian spaghetti is typically made from durum wheat semolina. Usually, the pasta is white because refined flour is used, but whole wheat flour may be added. Spaghettoni is a thicker form of spaghetti, while capellini is a very thin spaghetti.

Source: Wikipedia