Sui generis is a (post) Latin expression, literally meaning of its own gender/genus or unique in its characteristics. 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 its own genus.
In law, it is a term of art used to identify a legal classification that exists independently of other categorizations because of its uniqueness or due to the specific creation of an entitlement or obligation. In intellectual property there are rights which are known as being sui generis to owners of a small class of works, such as intellectual property rights in mask works, ship hull designs, databases, or plant species.
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