The word "Super" in regard to wool indicates that the fabric was spun at a high twist rate when the cloth was manufactured। This process produces a finer fabric that is softer and lighter than worsted wool. These fabrics are excellent for warmer climates.
The "S" number (ie. Super 100's) refers to the fineness of the wool in microns that the tuxedo is made from. The higher the number the finer the wool thread has been spun. For easy reference think of the way bed sheets get softer and smoother as the threads per square inch goes up. The same rules apply with the wool used in making tuxedos, higher the number = smoother finish.
This number should only be used a reference when selecting a tuxedo as the grade of the wool also plays a factor in the quality of the fabric. This is seen in some of the higher end tuxedos that are made from Super 100's fabric but feel and wear better than a tuxedo made from Super 150's fabric. Lora Piana is a top producing mill known throughout the formalwear and suit industry for its quality wool blends. Joseph Abboud and Lubiam use Lora Piana wools to make gorgeous tuxedos.