Cast is a short, common word with several distinct meanings across technology, society, medicine and culture. In general usage it can refer to the process of shaping material in a mold, the family of products that result from that process, a group of performers selected for a work, a medical device for immobilizing a limb, or a social division (caste). The same word has also been adopted as titles and names in popular culture.

Manufacturing and materials

In manufacturing, casting describes the technique of pouring a liquid material into a shaped cavity (a mold) where it solidifies into a desired geometry. This process applies to metals, plastics, glass and some ceramics. Typical steps include pattern making, mold preparation, pouring, cooling and finishing. Casting is valued for its ability to create complex forms, large parts and economical production of identical items.

  • Casting (manufacturing): methods include sand casting, die casting, investment casting and centrifugal casting.
  • Cast iron: an iron–carbon alloy commonly produced by casting; notable for good castability and compressive strength.

Performance and media

In the performing arts, casting is the pre-production activity of selecting performers to fill roles. A cast of a play, film or television production is the ensemble of actors chosen to portray the characters. Casting directors manage auditions and callbacks and work with directors and producers to match performers to roles based on skill, chemistry and interpretation.

Related terms include:

  • Cast member: an individual performer who is part of a production’s ensemble.

Medical use

An orthopedic cast is a rigid external shell applied to an injured limb to immobilize bones and joints to permit healing. Historically made of plaster of Paris and now commonly of synthetic fiberglass, casts are custom-fitted, trimmed and sometimes lined for comfort. They remain a standard non-surgical treatment for many fractures and severe sprains.

Archaeology and paleontology

In archaeological contexts, a cast can also mean a natural or artificial fill that preserves the shape of decomposed organic material. A well-known example is a hollow left by a buried wooden object or a body that later decomposed; when that cavity is filled with minerals or hardened ash it can form a cast that preserves the original form. Archaeologists sometimes create casts to study or exhibit fragile remains without disturbing the original matrix.

Social classification and other meanings

The word is sometimes confused with or linked to the term caste, a social stratification system found in some cultures; though pronounced similarly in some dialects, caste and cast are etymologically and conceptually distinct. Outside technical and social uses, "cast" appears in names and titles: for example, bands, comics and other creative works often adopt the word as a title or identifier.

Notable distinctions and practical notes

  • Context determines meaning: in engineering contexts "cast" usually refers to materials or parts; in entertainment it refers to people.
  • Materials and safety: different casting methods require different materials and safety precautions, and medical casts require monitoring for circulation and skin health.
  • Preservation: archaeological casts provide valuable three-dimensional records when original organic materials have disappeared.

Because "cast" covers technical, social and cultural domains, it is important to rely on contextual clues—industry, subject matter and surrounding vocabulary—when interpreting the term. For further reading on specific senses, follow links to detailed treatments of casting processes, cast iron metallurgy, social caste systems, performance casting, orthopedic practice, and archaeological casting techniques.