[people of common descent] 1560s, "people descended from a common ancestor, of persons allied by common ancestry," from French race, earlier razza "race, breed, lineage, family" (16c.), possibly from Italian razza, which is of unknown origin (cognate with Spanish raza, Portuguese raça). Etymologists say it has no connection with Latin radix "root," though they admit this might have influenced the "tribe, nation" sense, and race was a 15c. form of radix in Middle English (via Old French räiz, räis). Klein suggests the words derive from Arabic ra's "head, beginning, origin" (compare Hebrew rosh).
Original senses in English included "wines with characteristic flavor" (1520), "group of people with common occupation" (c. 1500), and "generation" (1540s). The meaning developed via the sense of "tribe, nation, or people regarded as of common stock" to "an ethnical stock, one of the great divisions of mankind having in common certain physical peculiarities" by 1774 (though as OED points out, even among anthropologists there never has been an accepted classification of these). In 19c. also "a group regarded as forming a distinctive ethnic stock" (German, Greeks, etc.).
Just being a Negro doesn't qualify you to understand the race situation any more than being sick makes you an expert on medicine. [Dick Gregory, 1964]
In mid-20c. U.S. music catalogues, it means "Negro." Old English þeode meant both "race, folk, nation" and "language;" as a verb, geþeodan meant "to unite, to join." Race-consciousness "social consciousness," whether in reference to the human race or one of the larger ethnic divisions, is attested by 1873; race-relations by 1897. Race theory "assertion that some racial groups are endowed with qualities deemed superior" is by 1894.