Difference between a sweater and a sweatshirt

Many clothing websites use distinct categories for both sweaters and sweatshirts. But what is the difference?

Solution 1:

A sweatshirt is made with sweatshirt fleece, which is a heavy fabric that is finished on one side and has a soft, fluffy nap on the other. The garment is designed to be worn with the finished side out and the napped side close to the skin, so the air trapped by the nap will help retain body heat. Despite the name, it does not have to be wool; sweatshirts can be made of cotton, synthetic fibers, or other materials.

A sweater is simply a knitted garment worn over the torso, typically one in which the yarn is thick enough that the knit pattern can be seen easily with the naked eye (unless it is obscured by the nap, as with fabrics such as angora and cashmere).

Solution 2:

This and only this is a sweatshirt to me:

It is NOT a hoodie.

Solution 3:

A Sweatshirt is a sweater or pullover with long sleeves. Some designs have front pouch, pockets for the hands or a hood, (sometimes called a "hoody" or ''hoodie'').

The sweater is formed by the linking of stitches - Its shape and pattern come from the structure of the garment. If the stitches are taken away there is no form. A sweatshirt has a pattern or logo printed onto it. The pattern has no relationship to the shape of the garment - if you remove it the sweatshirt remains intact.

The sweater is much more complex in it’s making than the sweatshirt, but has a more simple beauty.

See Here.