Why is the ninth month called September?
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" (cf. Old High German scopf "building without walls, porch," German dialectal Scopf "porch, cart-shed, barn," German Schuppen "a shed"), from 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.
Meaning "building or room set aside for sale of merchandise" is from mid-14c. Meaning "schoolroom equipped for teaching vocational arts" is from 1914, American English. Sense of "matters pertaining to one's trade" is from 1814 (as in talk shop (v.), 1860).
1680s, "to bring something to a shop, to expose for sale," from shop (n.). The meaning "to visit shops for the purpose of examining or purchasing goods" is first attested 1764. Related: Shopped; shopping. Shop around is from 1922. Shopping cart is recorded from 1956; shopping list first attested 1913; transferred and figurative use is from 1959.