Fashion Design and Apparel Design are quite different from each other. Fashion designers make designs for clothing, accessories, and help create new trends for the market.
Apparel Design, on the other hand, is more technical. You will learn to construct a design along with designing. This is the reason why big houses prefer to hire Apparel Designers instead of Fashion designers.
The designers working in a team to create a line under big houses like Puma, Gap, Nike are referred to as Apparel Designers.