Class, Leaf, Node
An individual piece of a hierarchy under which exist further categories or items.
Categories serve to organize items or concepts in similar clusters. Typically, only categories at the lowest levels of a hierarchy, terminal categories, contain items. All other categories generally have further categories beneath them. For example, there may be a category called [Produce] under which exist [Fruit] and [Vegetables], both of which house additional categories in which items are classified, e.g. [Apples], [Bananas], [Cucumbers].
Child Category, Cross-list, Parent Category, Sibling Category, Solutions Category, Terminal Category, Mega Category