Category
page 1Higher category theory
category theory
branch of mathematics studying categories, functors, and natural transformations
John C. Baez
American mathematician and mathematical physicist

Jacob Lurie
American mathematician
quasi-category
In mathematics, more specifically category theory, a quasi-category (also called quasicategory, weak Kan complex, inner Kan complex, infinity category, ∞-category, Boardman complex, quategory) is a generalization of the notion of a category. The study of such generalizations is known as higher category theory.
higher category theory
generalization of category theory for higher-order morphisms
strict 2-category
In category theory in mathematics, a 2-category is a category with "morphisms between morphisms", called 2-morphisms. A basic example is the category Cat of all (small) categories, where a 2-morphism is a natural transformation between functors.