early 14c., "actually existing, having physical existence (not imaginary);" mid-15c., "relating to things" (especially property), from Old French reel "real, actual," from Late Latin realis "actual," in Medieval Latin "belonging to the thing itself," from Latin res "property, goods, matter, thing, affair," which de Vaan traces to a PIE *Hreh-i- "wealth, goods," source also of Sanskrit rayim, rayah "property, goods," Avestan raii-i- "wealth."
The meaning "genuine" is recorded from 1550s; the sense of "unaffected, no-nonsense" is from 1847. Real estate, the exact term, "land, including what is naturally or artificially on or in it" is recorded from 1660s, but as far back as Middle English real was used in law in reference to immovable property, paired with, and distinguished from, personal. The noun phrase real time is from early 19c. in logic and philosophy, from 1953 as an adjectival phrase in reference to "the actual time during which an event or process occurs," with the rise of computer processes. Get real, usually an interjection, was U.S. college slang in 1960s, reaching wide popularity c. 1987. As a noun, the real, "that which actually exists," by 1818 (Coleridge). The real thing "the genuine article" is by 1818.
Real applies to that which certainly exists, as opposed to that which is imaginary or feigned : as, real cause for alarm ; a real occurrence ; a real person, and not a ghost or a shadow ; real sorrow. Actual applies to that which is brought to be or to pass, as opposed to that which is possible, probable, conceivable, approximate, estimated, or guessed at. [Century Dictionary]
Generally, by the time you are Real, most of your hair has been loved off, and your eyes drop out and you get loose in the joints and very shabby. But these things don't matter at all, because once you are Real you can't be ugly, except to people who don't understand. [Margery Williams, "The Velveteen Rabbit"]
"small silver coin and money of account in Spain and Spanish America," 1580s, from Spanish real, noun use of real (adj.) "regal," from Latin regalis "regal" (see regal). Especially in reference to the real de plata, which circulated in the U.S. till c. 1850 and in Mexico until 1897. The same word was used in Middle English in reference to various coins, from Old French real, a cognate of the Spanish word.
The old system of reckoning by shillings and pence is continued by retail dealers generally; and will continue, as long as the Spanish coins remain in circulation. [Bartlett, "Dictionary of Americanisms," 1848]
He adds that, due to different exchange rates of metal to paper money in the different states, the Spanish money had varying names from place to place. The Spanish real of one-eighth of a dollar or 12 and a half cents was a ninepence in New England, one shilling in New York, elevenpence or a levy in Pennsylvania, "and in many of the Southern States, a bit." The half-real was in New York a sixpence, in New England a fourpence, in Pennsylvania a fip, in the South a picayune.