All three refer to fabrics made from nylon, differing primarily in the fiber's glossiness:

Glossy: Similar to polyester gloss, with a smooth fiber surface that creates a strong sheen.
Matt: Similar to polyester matte, with a high percentage of a matting agent (such as titanium dioxide) added, resulting in a low-gloss finish that's almost matte.
Semi-gloss: Similar to polyester semi-gloss, with a glossiness between glossy and matte, exhibiting a soft sheen.