Glaze as a verb and in the kitchen, means to give food a smooth, shiny, often transparent finish.
This can be achieved in various ways, one of which is to apply a coating of something which has these qualities, for example aspic, often used over fish.
Other examples of cold glazes are coating a cake with a suitable jam such as apricot; or applying a fruit syrup glaze (made by reducing the syrup in which fruit has been poached and then thickening with arrowroot) to, say, a cooked pastry shell.
Many kinds of glaze require heat to be effective. Thus, if vegetables are cooked with butter and sugar they will emerge with a shiny finish. Loaves of bread or buns may be coated with beaten egg or milk, or the like, before being baked; and the process of baking turns the coating into a glaze (using white of egg alone gives a clear glaze, whole egg gives medium brown, and yolk alone a rich brown). Similarly, if a dessert has sugar sprinkled on it and is then put briefly under a hot grill, it will acquire a shiny glaze, which will be brown underneath a transparent surface.