The protocol for naming an enzyme is to give the name of the substance the enzyme breaks down, with the suffix "-ase". So amylase breaks down amylum (starch), lactase breaks down lactose, and so on. All of these enzymes are used to quickly break down large, complex molecules into their smaller components.
Amylase is added to bread dough, where is breaks some of the starch in the flour down into sugars, which are then available to the yeast, which metabolise the sugars and make the dough rise.
Lactase has two common industrial uses. Lactose is added to ice cream mixtures to facilitate breaking lactose down into glucose and galactase, which taste better at low temperatures and are less likely to crystallise when frozen. The other use is to create dairy products which are more digestible for lactose-intolerant consumers.
Proteases are used to break down large protein molecules. They are used to speed up the development of milk into cheese, and also as meat tenderizers, making cheaper, leaner cuts of meat have a better texture.
Cellulase breaks down cellulose or woody fiber. Cellulase is used on coffee beans to help release the flavor-containing oils from the bean, and on other beans to allow them to be cooked more quickly. Cellulase is also used during wine production to promote the release of tannins and other molecules from the skin of the grapes.