Waterjet is a generic term used to describe equipment that uses a high pressure stream of water for cutting or cleaning purposes. Abrasivejet is a subcategory of waterjet in which abrasive is introduced to accelerate the process. Waterjets can cut just about any material that can be made into a sheet and placed in front of them.
The most popular materials are metals (especially aluminum, because it’s relatively soft and cuts quickly), because waterjets can cut intricate shapes to a high precision quickly and economically. Since metals are the most common material cut by machining shops, waterjets tend to cut a lot of metal.
Waterjets also commonly cut stone and glass, because the waterjet can get intricate shapes not possible using traditional machining methods. These materials are popular with artists who like to work with these materials and waterjets because it lets them create almost anything they can envision.