Knit fabric has loops of fiber that allow the fabric to stretch. The amount of stretch and the direction of stretch are all variables. A knit may stretch in one direction or it may stretch in both directions. This is an important consideration when choosing fabric for a specific pattern. For example; A bathing suit pattern will require equal two way stretch. If you choose a fabric that only stretches in one direction, the suit is not going to fit properly... if you can even get it on.