casing

Casing is a term used across multiple domains to describe a protective outer layer, wrapper, or enclosing structure that surrounds, protects, or finishes an object. The precise meaning varies by field but generally involves containment or framing.

In food production, casing refers to the material used to encase ground meat or other fillings, forming sausages, salamis, and similar products. Natural casings are derived from animal intestines; artificial casings include collagen, cellulose, or plastic.

In architecture and interior finishing, door and window casing is the trim around an opening. It covers rough framing and gaps, contributes to aesthetics, and can be constructed from wood, plaster, or composite materials.

In mechanical and utility work, casing denotes the protective sheath or lining around cables, pipes, or ducts. This outer layer shields contents from damage, provides insulation, and helps with organization and installation.

In oil and gas drilling, the well casing is a series of steel pipes cemented into the borehole. It stabilizes the well, isolates formations, and prevents fluids from migrating between layers.

In firearms, the cartridge case surrounds the primer, propellant, and bullet. Typically metal, it provides containment for the explosive reaction and is ejected after firing.

In typography and computing, 'case' refers to capitalization: uppercase versus lowercase. 'Casing' is used to describe processes that convert text into a particular case, such as uppercasing, lowercasing, or title casing.