An arrangement whereby the main responsibility for welfare payments, especially unemployment benefits, is held by trade or labour unions rather than a government agency.

(mathematics) a set of equations required to be satisfied simultaneously or considered as a whole

(computing) A system for computing that includes the physical computing unit itself and its peripherals. / (computing) Any system based around computer technology, such as a software package.

(Indo-European studies) A system which describes how certain Proto-Indo-European words are derived from one another.

(astronomy) A geocentric model of the solar system, described by the eponymous astronomer.

The hierarchical organization of the kitchen staff in a restaurant into small teams or individuals, each responsible for a type of food (starters, mains etc) under the overall control of a head chef.

(rail transport) A rail system used in mountainous terrain with multiple cograils.

(crystallography) Any of the seven distinct symmetry classifications of crystals: cubic, tetragonal, hexagonal, orthorhombic, monoclinic, triclinic and trigonal.

(linguistics) A system for writing one or more languages; a particular alphabetic, syllabic, logographic, or other scheme. For example, the Latin alphabet or the Cyrillic alphabet.

(astronomy) Two gravitationally connected stars or other celestial objects which orbit around their center of mass.