Demi-glace is a French word which literally means "half glace". It refers to a rich brown sauce that begins with a basic espagnole sauce, which is combined with beef stock and Madeira or Sherry and slowly cooked until it`s reduced by half to a thick glaze that coats a spoon. This intense flavor is used as a base for many other sauces.

Demi-glace is proununced "dehm-ee glahs"