Tray

Tray
A tray is a shallow platform designed for carrying things. It is larger than a salver, a diminutive version commonly used for lighter and smaller servings, and it can be fashioned from numerous materials, including silver, brass, sheet iron, wood, melamine, and papier-mâché. Some examples have raised galleries, handles, and short feet for support.

Trays are flat, but with raised edges to stop things from sliding off of them. They are made in a range of shapes but are commonly found in oval or rectangular forms, sometimes with cutout or attached handles with which to carry them.
A butler's tray often has a gallery, or deeper surround, handles on the short sides to facilitate carrying (usually cut into the surround), and a portable stand with folding legs. It is used for the service of drinks and generally serves as a convenient side table.
A cafeteria tray is used for carrying items in a cafeteria. It is typically made of plastic or fiberglass.
In horticulture, trays are used for propagating vegetables and flowers from seed. The trays for seedling production are made of expanded polystyrene or polythene. They come in many sizes; the most common are the Danish and the European sized trays.
Surgical trays, used to carry surgical instruments, are rectangular and made of stainless steel to resist the heat of sterilization without corrosion.