Real Dictionary

diversity
an alphabetical list of persons, places, subjects, etc, mentioned in the text of a printed work, usually at the back, and indicating where in the work they are referred to [...]
an arrangement of repeated or corresponding parts, decorative motifs, etc [...]
the state or quality of being different or varied [...]
singular noun: A diversity of things is a range of things which are very different from each other.
uncountable noun: Diversity involves the deliberate inclusion in a group or activity of people who are, for example, of different races, genders, and religions.
variable noun: The diversity of something is the fact that it contains many very different elements.