Sui generis

Sui generis is a (post) Latin expression, literally meaning Of its own gender/genus. Unique, characteristic.

In law, a grant of exclusive rights ("intellectual property") to owners of a small class of works, such as mask work, ship hull design[?], databases, or plant species.

The expression was effectively created by scholastic philosophy to indicate an idea, an entity or a reality that cannot be included in a wider concept, and in the structure genus > species a species that heads an own genus.

In British town planning law, certain uses of land are labelled "sui generis" to indicate that they are outside a legally-defined Use Class, effectively in a class of their own. Under this style of regulation, changes of land use within an agreed "Use Class[?]" can be undertaken without an explicit application being made to a local municipal authority. Changes in the use of a property or site across the boundaries of those Use Classes, or to a "sui generis" activity, can thus be subject to some democratic influence.

See also: List of Latin phrases