mestizo adj.

also *meig-, Proto-Indo-European root meaning "to mix." 

It forms all or part of: admix; admixture; immiscible; mash; meddle; medley; melange; melee; mestizo; metis; miscegenation; miscellaneous; miscible; mix; mixo-; mixture; mustang; pell-mell; promiscuous.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit misrah "mixed;" Greek misgein, mignynai "to mix, mix up, mingle; to join, bring together; join (battle); make acquainted with;" Old Church Slavonic mešo, mesiti "to mix," Russian meshat, Lithuanian maišau, maišyti "to mix, mingle," Welsh mysgu "to mix." 

also mestee, "octoroon, offspring of a white and a quadroon," also, generally, "a half-caste," 1690s, a West Indian word, a corruption of Spanish mestizo (q.v.).

"person of mixed parentage," especially French Canadian and North American Indian, 1816, from French métis, from Late Latin mixticus "of mixed race," from Latin mixtus "mixed," past participle of miscere "to mix, mingle" (from PIE root *meik- "to mix"). Compare mestizo.