XL - 14/16, 2XL = 18/20, 3XL = 22/24, 4XL = 26/28, 5XL = 30/32, 6XL = 34/36. (Though we know they aren't the same, for our organizational purposes, we put XL & 1XL together and 2XL & XXL together. )
3XL is women's triple extra large and roughly translates to women's sizes 22–24 or larger.
Here's how we arrange our sizing: XL - 14/16, 2XL = 18/20, 3XL = 22/24, 4XL = 26/28, 5XL = 30/32, 6XL = 34/36.
An XXL is a Misses 18. A 1X is a plus size 14/16. The difference is that plus size clothing is generally made wider and with more room in the arms, hips, thighs, butt, and stomach areas.
A: They are both women sizes: 3x and xxxl are the same except xxxl has longer sleeves and the body of the item is longer because the (l) in the xxxl usually stands for long.
Fit models for plus are generally a size 2X or 18/20, meaning that this fit model definitely has a curvier figure. Because curves are taken into account in in-style plus size clothing, you will notice a difference in fit. Plus sizes generally give a bit more room in the armhole, but the sleeve won't be too long.