A heel is the bottom, back part of a shoe or boot that provides elevation. The styling and construction of a heel may vary (i.e., stacked, stilletto, spiked, sculptured, kitten).
About Sandals:
An open type of shoe that consists of a sole fastened by straps to the foot. Types of sandals include espadrilles, flip-flops, strappy sandals, and thong sandals.
About Slides:
A backless, open-toed shoe that is generally a type of sandal. Slides can be high heeled, flat heeled, or somewhere inbetween; may cover nearly the entire foot from ankle to toe; or may have only one or two narrow straps.