c. 1300, "belonging to all, owned or used jointly, general, of a public nature or character," from Old French comun "common, general, free, open, public" (9c., Modern French commun), from Latin communis "in common, public, shared by all or many; general, not specific; familiar, not pretentious." This is from a reconstructed PIE compound *ko-moin-i- "held in common," compound adjective formed from *ko- "together" + *moi-n-, suffixed form of root *mei- (1) "to change, go, move," hence literally "shared by all."
The second element of the compound also is the source of Latin munia "duties, public duties, functions," those related to munia "office." Perhaps reinforced in Old French by the Germanic form of PIE *ko-moin-i- (compare German gemein, Old English gemne "common, public, general, universal;" see mean (adj.)), which came to French via Frankish.
Used disparagingly of women and criminals since c. 1300. Meaning "pertaining equally to or proceeding equally from two or more" is from c. 1400. Meaning "usual, not exceptional, of frequent occurrence" is from late 14c. Sense of "not distinguished, belonging to the general mass" is from c. 1400; of things, "ordinary, not excellent," late 14c.
Common pleas is 13c., from Anglo-French communs plets, hearing civil actions by one subject against another as opposed to pleas of the crown. Common prayer is that done in public in unity with other worshipers; contrasted with private prayer. Common stock is attested from 1888. Common speech (late 14c.) is the vernacular, as opposed to Latin. Common good (late 14c.) translates Latin bonum publicum "the common weal." The college common room (1660s) is one to which all members have common access.
early 12c., "a meeting at a fixed time for buying and selling livestock and provisions, an occasion on which goods are publicly exposed for sale and buyers assemble to purchase," from Old North French market "marketplace, trade, commerce" (Old French marchiet, Modern French marché), from Latin mercatus "trading, buying and selling; trade; market" (source of Italian mercato, Spanish mercado, Dutch markt, German Markt), from past participle of mercari "to trade, deal in, buy," from merx (genitive mercis) "wares, merchandise." This is from an Italic root *merk-, possibly from Etruscan, referring to various aspects of economics.
The god Mercurius was probably the god of exchange. According to [Walde-Hoffmann], the god's name was borrowed from Etruscan; in principle, the same is possible for the stem *merk- altogether. [de Vaan]
Meaning "public building or space where markets are held" is attested from late 13c. Meaning "a city, country or region considered as a place where things are bought or sold" is from 1610s. Sense of "sale as controlled by supply and demand" is from 1680s. Market-garden "plot of land on which vegetables are grown for market" is by 1789. Market-basket "large basket used to carry marketing" is by 1798. Market price "price a commodity will bring when sold in open market" is from mid-15c.; market value "value established or shown by sales" (1690s) is first attested in the writings of John Locke. Market economy is from 1948; market research is from 1921.
c. 1300, "a fellowship or brotherhood; early 14c., "people of a community or town, freemen, citizenry;" late 15c., "land held in common," from Old French commune and Medieval Latin communia, and partly from common (adj.). Also compare commons. Latin communis "common, general" (adj.) also served as a noun meaning "common property; state, commonwealth."
mid-14c., "the customary and unwritten laws of England as embodied in commentaries and old cases" (see common (adj.)), as opposed to statute law. Phrase common-law marriage is attested from 1909.
1839, from common sense, with ending as in nonsensical, etc. Common-sensible is attested from 1848.
late 14c., originally an internal mental power supposed to unite (reduce to a common perception) the impressions conveyed by the five physical senses (Latin sensus communis, Greek koine aisthesis). Thus "ordinary understanding, without which one is foolish or insane" (1530s); the meaning "good sense" is from 1726. Also, as an adjective, common-sense "characterized by common sense" (1854).