A tray is a shallow platform designed for carrying things. It is larger than a salver

Salver

A salver is a flat tray of silver or other metal used for carrying or serving glasses, cups and dishes at table or for the presenting of a letter or card by a servant...

, 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

Melamine

Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 66% nitrogen by mass and, if mixed with resins, has fire retardant properties due to its release of nitrogen gas when burned or charred, and has several other industrial uses....

, and papier-mâché

Papier-mâché

Papier-mâché , alternatively, paper-mache, is a composite material consisting of paper pieces or pulp, sometimes reinforced with textiles, bound with an adhesive, such as glue, starch, or wallpaper paste....

. 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

Rectangle

In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...

 forms, sometimes with cutout or attached handles with which to carry them.

Examples

• 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
  Cafeteria
  A cafeteria is a type of food service location in which there is little or no waiting staff table service, whether a restaurant or within an institution such as a large office building or school; a school dining location is also referred to as a dining hall or canteen...
  
  . It is typically made of plastic
  Plastic
  A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
  
   or fiberglass
  Fiberglass
  Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
  
  . A compartment tray or mess tray is a cafeteria tray designed to be used directly, without dishes - it incorporates shallow compartments in which different types of food are placed.

• A Lazy Susan
  Lazy Susan
  A Lazy Susan is a rotating tray, usually circular, placed on top of a table to aid in moving food on a large table or countertop.- Origin :The term "Lazy Susan" made its first written appearance in a Good Housekeeping article in 1906, although their existence dates back to the 18th century...
  
  is a rotating tray, usually circular, placed on top of a table to aid in moving food on a large table or countertop.

• Surgical trays, used to carry surgical instruments, are rectangular and made of stainless steel
  Stainless steel
  In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
  
   to resist the heat of sterilization
  Sterilization (microbiology)
  Sterilization is a term referring to any process that eliminates or kills all forms of microbial life, including transmissible agents present on a surface, contained in a fluid, in medication, or in a compound such as biological culture media...
  
   without corrosion
  Corrosion
  Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
  
  .

• In horticulture
  Horticulture
  Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
  
  , seed trays are used for propagating vegetables and flowers and other plants from seed
  Sowing
  Sowing is the process of planting seeds.-Plants which are usually sown:Among the major field crops, oats, wheat, and rye are sowed, grasses and legumes are seeded, and maize and soybeans are planted...
  
  . They are also used for taking plant cuttings. 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.

• A darkroom tray, also known as print developing tray, used in photography
  Photography
  Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
  
  .