Wiktionary
alt. 1 With respect to a given category, a more narrow category. 2 (context category theory English) A subclass of a category which is itself a category, whose arrows are a restriction of the arrows of the parent category, and whose composition rule is a restriction of the parent category's n. 1 With respect to a given category, a more narrow category. 2 (context category theory English) A subclass of a category which is itself a category, whose arrows are a restriction of the arrows of the parent category, and whose composition rule is a restriction of the parent category's
Wikipedia
In mathematics, a subcategory of a category C is a category S whose objects are objects in C and whose morphisms are morphisms in C with the same identities and composition of morphisms. Intuitively, a subcategory of C is a category obtained from C by "removing" some of its objects and arrows.
Usage examples of "subcategory".
Because of where the crimes took place, we have to strongly consider that they may be domestic homicides, a subcategory of personal-cause homicides.
The relationship is reciprocal: statism rises out of prehistorical tribal warfare, out of the notion that the men of one tribe are the natural prey for the men of another—and establishes its own internal subcategories of racism, a system of castes determined by a man’s birth, such as inherited titles of nobility or inherited serfdom.