Pasta" is the Italian word for "paste." All pasta is made from dough of grain flour mixed with water. There are many different shapes and sizes of pasta. While most are made from wheat, other grains can also be used on their own (for people who are gluten intolerant) or combined with wheat.
Take dough made from grain; force it through a variety of differently shaped molds and out come nifty noodles of varying shapes -- flat, smooth, solid, hollow, and twisted. Give to these wiggly forms melodious Italian names, and you have the many kinds of pasta that sit on the supermarket shelf. The shape of the noodles determines the name of the pasta: