I am, by no means, and expert on weaving but the term Worsted describes three separate things.

1 A yarn used in weaving.
Here a Worsted Yarn is one where all the fibers have been combed to insure they are straightened and parallel.

2 A type of fabric
Here a cloth made from Worsted yarn is usually a Twill Weave and because the yarns are from straight and parallel fibers spun very tightly the fabric will recover from wrinkling very easily.

3 A weight of fabric
A fabric which is made from fibers at least three inches long, using Worsted yarns and having a size or Gauge of 16-20 stitches per 10 centemeters using a US size 9 needle

Whoa!!! information overload.
Basically Worsteds and Woolens are two different things. Worsting produces a fabric which has a very tight weave, a knubbly or "coarse" surface and has good wrinkle resistance.
Woolens on the other hand, "Breathe" better, are better insulators, and have a softer or more fleecy "hand".