barber-shop (n.)

"one whose occupation is to shave the beard and cut and dress the hair," c. 1300, from Anglo-French barbour (attested as a surname from early 13c.), from Old French barbeor, barbieor (13c., Modern French barbier, which has a more restricted sense than the English word), from Vulgar Latin *barbatorem, from Latin barba "beard" (see barb (n.)).

Originally also regular practitioners of minor surgery, they were restricted to hair-cutting, blood-letting, and dentistry under Henry VIII. The barber's pole (1680s) is in imitation of the ribbon used to bind the arm of one who has been bled.

c. 1300, "booth or shed for trade or work," perhaps from Old English scoppa, a rare word of uncertain meaning, apparently related to scypen "cowshed," from Proto-Germanic *skoppan "small additional structure" (source also of Old High German scopf "building without walls, porch," German dialectal Scopf "porch, cart-shed, barn," German Schuppen "a shed"), from a root *skupp-. Or the Middle English word was acquired from Old French eschoppe "booth, stall" (Modern French échoppe), which is a Germanic loan-word from the same root.

The meaning "building or room set aside for sale of merchandise" is from mid-14c. The meaning "schoolroom equipped for teaching vocational arts" is from 1914, American English (as in shop class, attested by 1948).

The sense of "one's own business, craft, or calling" is from 1814, as in talk shop (v.), "converse in general society about matters pertaining to one's trade," which is attested in this sense by 1847. Shop-talk (n.) is by 1881.

Lawyers, I am happy to say, seldom talk shop to each other. I have a notion that if they did, they would mutually send each other small bills for opinion and advice given ; and then go into court to have a fair stand-up battle for the thirteen-and-four-pences. [Angus B. Reach, "The Natural History of Humbugs," 1847]