Sui generis

Sui generis (/ˌsuːi ˈʒɛnərɪs/ SOO-ee ZHEN-ər-iss,^[1] Classical Latin: [ˈsʊ.iː ˈɡɛnɛrɪs]) is a Latin phrase that means "of its/their own kind" or "in a class by itself", therefore "unique".^[2] It denotes an exclusion to the larger system an object is in relation to.

Several disciplines use the term to refer to unique entities. These include:

Biology, for species that do not fit into a genus that includes other species^[3] (its own genus)
Creative arts, for artistic works that go beyond conventional genre boundaries (its own genre)
Law, when a special and unique interpretation of a case or authority is necessary (its own special case)
- Intellectual property rights, for types of works not falling under general copyright law but protected through separate statutes and laws of war, for types of actions that are argued to be legal due to exceptional circumstances in conflict
Philosophy, to indicate an idea, an entity, or a reality that cannot be reduced to a lower concept or included in a higher concept (its own category)

^ "sui generis". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
^ Mawson, C. O. Sylvester (1975). "sui generis". Dictionary of Foreign Terms (2 ed.). New York: Thomas Y. Crowell Company. p. 328. ISBN 0-690-00171-1.
^ Bentham, George (1880). "Notes on Euphorbiaceæ". Journal of the Linnean Society, Botany. 17: 225 – via Google.