mid-14c., diversite, "variety, diverseness;" late 14c., "quality of being diverse, fact of difference between two or more things or kinds; variety; separateness; that in which two or more things differ," mostly in a neutral sense, from Old French diversete "difference, diversity, unique feature, oddness:" also "wickedness, perversity" (12c., Modern French diversité), from Latin diversitatem (nominative diversitas) "contrariety, contradiction, disagreement;" also, as a secondary sense, "difference, diversity," from diversus "turned different ways" (in Late Latin "various"), past participle of divertere (see divert).

A negative meaning, "perverseness, being contrary to what is agreeable or right; conflict, strife; perversity, evil" existed in English from late 14c. but was obsolete from 17c. Diversity as a virtue in a nation is an idea from the rise of modern democracies in the 1790s, where it kept one faction from arrogating all power (but this was not quite the modern sense, as ethnicity, gender, sexual identity, etc. were not the qualities in mind):

The dissimilarity in the ingredients which will compose the national government, and still more in the manner in which they will be brought into action in its various branches, must form a powerful obstacle to a concert of views in any partial scheme of elections. There is sufficient diversity in the state of property, in the genius, manners, and habits of the people of the different parts of the Union, to occasion a material diversity of disposition in their representatives towards the different ranks and conditions in society. ["The Federalist," No. 60, Feb. 26, 1788 (Hamilton)]

Specific focus (in a positive sense) on race, gender, etc., "inclusion and visibility of persons of previously under-represented minority identities" is by 1992.

also bio-diversity, "the range of variety in the living organisms of a given area," by 1988, from bio- + diversity.

early 15c., "characterized by variety," from Latin varius "changing, different, diverse" (see vary). Meaning "different from one another, having a diversity of features" is recorded from 1630s. Related: Variously.

"diversity of forms; variety of shapes or appearances in one thing," 1580s, from Late Latin multiformitas, from Latin multiformis "many-shaped; manifold; various, diverse," see multi- + form (n.).

late 14c., "difference, divergence," from Old French variacion "variety, diversity" and directly from Latin variationem (nominative variatio) "a difference, variation, change," from past participle stem of variare "to change" (see vary). The musical sense is attested from 1801. Related: Variational.

1640s, "making or exhibiting a difference," from Medieval Latin differentialis, from Latin differentia "diversity, difference" (see difference). Related: Differentially. As a noun in mathematics, "an infinitesimal difference between two values of variable quantity," from 1704. Differential calculus is attested from 1702.

"difference or separation in opinion," 1650s, from Latin dissidentia "diversity, contrariety," from dissidens, present participle of dissidere "to be remote; disagree, be removed from," literally "to sit apart," from dis- "apart" (see dis-) + sedere "to sit," from PIE root *sed- (1) "to sit."

1530s, "change of fortunes," from French variété and directly from Latin varietatem (nominative varietas) "difference, diversity; a kind, variety, species, sort," from varius "various" (see vary). Meaning diversity, absence of monotony" is from 1540s; that of "collection of different things" is from 1550s; sense of "something different from others" is from 1610s. In reference to music hall or theatrical performances of a mixed nature, first recorded 1868, American English. The U.S. theater and entertainment industry magazine was founded in 1905 by Sime Silverman.

Variety's grammar is barbarous; its style is original and unique and completely independent of any other writing; its phraseology is wild and revolutionary and its diction is the result of miscegenation among shop talk, slang, Broadway colloquialisms, sporting neologisms and impatient short-cutting. [Hugh Kent, "Variety," American Mercury, December 1926] 

c. 1300, Macedone, from Latin Macedonius "Macedonian," from Greek Makedones "the Macedonians," literally "highlanders" or "the tall ones," related to makednos "long, tall," makros "long, large" (from PIE root *mak- "long, thin"). Macédoine "mixed cut fruit or vegetables" is by 1846, from French, said to be a reference to the diversity of people in Alexander's empire.

"vessel used for holding liquids," late 14c., from Medieval Latin phiola, from Latin phiala, from Greek phialē "flat vessel, dish, flat bowl for drinking or sacrificing," a loan-word of unknown origin. It also came to Middle English via Old French fiole "flask, phial" (12c.), hence the diversity of Middle English spellings (fiole,phiole,phial,fial,viole,vial,viele) and modern vial.