Sui generis
Latin: Of its own kind.
Of its own kind. Describes something unique that does not fit any existing legal category and must be understood on its own terms.
Explained
Sui generis means of its own kind or in a class by itself. Lawyers use it for an institution, right or legal relationship that does not fit into any established category, so that rules framed for those categories cannot simply be applied to it.
A leading Indian use is in constitutional law. In Government of NCT of Delhi v. Union of India (2018) the Constitution Bench held, under Article 239AA, that the National Capital Territory of Delhi cannot be accorded the status of a State, that its status is sui generis, and that the Lieutenant Governor is not a Governor of a State but an Administrator in a limited sense. Delhi is thus neither an ordinary Union territory nor a State, and its position has to be worked out from Article 239AA itself.
The term is also common in intellectual property. Article 27(3)(b) of the TRIPS Agreement allows members to protect plant varieties either by patents or by an effective sui generis system, or both. India excludes plants and seeds, varieties and species from patentability under Section 3(j) of the Patents Act, 1970, and protects plant varieties through a separate law, the Protection of Plant Varieties and Farmers' Rights Act, 2001, which is described as a sui generis system. Courts and writers also call certain statutory schemes or bodies sui generis when they combine features of different categories.
The expression should not be confused with ejusdem generis, the rule of construction that confines general words to the genus of the specific words before them. Sui generis describes a thing; ejusdem generis is a method of reading words. Examiners ask for the literal meaning in matching questions and sometimes its use for Delhi's constitutional status.
What the law says
[(1) As from the date of commencement of the Constitution (Sixty-ninth Amendment) Act, 1991, the Union territory of Delhi shall be called the National Capital Territory of Delhi (hereafter in this Part referred to as the National Capital Territory) and the administrator thereof appointed under article 239 shall be designated as the Lieutenant Governor.
(2)(a) There shall be a Legislative Assembly for the National Capital Territory and the seats in such Assembly shall be filled by members chosen by direct election from territorial constituencies in the National Capital Territory.
(b) The total number of seats in the Legislative Assembly, the number of seats reserved for Scheduled Castes, the division of the National Capital Territory into territorial constituencies (including the basis for such division) and all other matters relating to the functioning of the Legislative Assembly shall be regulated by law made by Parliament.
Special provisions for Delhi, whose status is held sui generis
The following are not inventions within the meaning of this Act,—
(a) an invention which is frivolous or which claims anything obviously contrary to well established natural laws;
[(b) an invention the primary or intended use or commercial exploitation of which would be contrary to public order or morality or which causes serious prejudice to human, animal or plant life or health or to the environment;]
Clause (j) excludes plants and varieties, left to a sui generis law
For the exam
- Meaning: of its own kind; unique.
- GNCT of Delhi v. Union of India (2018): Delhi's status under Article 239AA is sui generis.
- TRIPS Article 27(3)(b): plant varieties by patents or an effective sui generis system.
- India's sui generis plant variety law is the PPVFR Act, 2001; Section 3(j) Patents Act excludes plants.
- Not to be confused with ejusdem generis, a rule of interpretation.
10 questions in the Law Maker question bank use this maxim. Practise Legal Maxims & Jurisprudence questions
Judgments
Related terms
- Ejusdem generisA rule of interpretation: where general words follow specific words of a distinct class, the general words are read as limited to things of the same class as the specific words.
- Union territoryAny Union territory specified in the First Schedule to the Constitution, including any other territory within India not specified in that Schedule. Article 366(30) of the Constitution.
- The State (Article 12)For Part III of the Constitution, the Government and Parliament of India, the Government and Legislature of each State, and all local or other authorities in India or under the control of the Government of India.
- InventionUnder Section 2(1)(j) of the Patents Act, 1970, a new product or process involving an inventive step and capable of industrial application.
- Noscitur a sociisA word is known by the company it keeps. The meaning of a doubtful word in a statute may be gathered from the words associated with it.
Further reading
Checked 6 November 2026. Statutory text is quoted from the Bare Acts library, taken from India Code. See the full glossary.