Sui generis

Sui generis (/ˌsuːi ˈdʒɛnərɪs/ SOO-ee JEN-ər-iss, Classical Latin: [ˈsʊ.iː ˈɡɛnɛrɪs]) is a Latin phrase that means 'of its/their own kind' or 'in a class by itself', therefore 'unique'.

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 (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
• 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)