Many of us refer to relaxers and perms as the same thing but, believe it or not they have two different meanings.
A permanent weave is often times referred to as a perm. Perms are used to add curl to hair that is naturally straight. This is done by using a liquid that is applied to the hair along with rods or rollers. The hair then takes the shape of the rods or rollers and is neutralized. A perm usually lasts until it grows out or cut.
A relaxer is a permanent straightener for hair that is tightly coiled. This works when at least 60% of the coils are straightened. Like a perm, a relaxer lasts until the hair grows out or until it is cut.
As you can see, both processes are completely different. I hope this helps you understand the difference between relaxers and perms.