What does "Sui Generis" Mean?

The Latin phrase sui generis, translated as “of its own kind,” is used in law to describe special legal situations. When something is considered sui generis, it falls outside normal legal guidelines and must be considered on a unique basis. Courts considering a variety of legal matters may weigh this consideration and it is also involved in patent law, where the unique nature of applications is an important factor in whether they will be approved.

When something is sui generis, it defies categorization. In a common example, sometimes a city will zone certain areas of land with this designation. This land isn't zoned with a specific term like residential, light industrial, or commercial. It is considered unique, and any use of the land must be approved by a planning commission, determining whether the use is appropriate for the setting and the character of the land.

As a legal classification, this term can be used to set something aside in a distinctive class. In courts, cases on a sui generis basis have to be evaluated carefully. The court wants to confirm the unique nature of the case to avoid creating confusion and must also be able to weigh the matter without being able to rely on similar cases, because there are none. Some courts may be reluctant to hear such cases out of concern about setting a dangerous precedent.

Seeing this term is a flag that something is considered to be part of a special class, meaning that it will be hard to find a basis for comparison. Things in similar classes can be identified, but they will not be the same. The term usually indicates that something must be reviewed carefully, whether one is talking about a sui generis zoning classification or an evaluation of a case presented to a court.

In the world of patents, protection is offered to new inventions and ideas on the basis of their originality. Failing to prove that something is original and involves a novel idea not previously known to members of the public can result in a denial of protections on the grounds that the application is lacking sui generis. It cannot stand on its own as a unique invention or development, because something else is similar or the information is generally available to the public and thus cannot be considered new or revolutionary. People cannot, for example, patent pants, because the basic concept and design is very well known, but they can patent a unique fabric or sewing technique.