3, 5. As a collective noun, variety, when preceded by a, is often treated as a plural: A variety of inexpensive goods are sold here. When preceded by the, it is usually treated as a singular: The variety of products is small. See also collective noun, number.
1533, from M.Fr. variété, from L. varietatem (nom. varietas) "difference, diversity," from varius "various" (see vary). First recorded 1868, Amer.Eng., in ref. to "music hall or theatrical performances of a mixed nature."