c. 1300, in chess, "a call noting one's move has placed his opponent's king (or another major piece) in immediate peril," from Old French eschequier "a check at chess" (also "chess board, chess set"), from eschec "the game of chess; chessboard; check; checkmate," from Vulgar Latin *scaccus, from Arabic shah, from Persian shah "king," the principal piece in a chess game (see shah; also compare checkmate (n.)). Also c. 1300 in a generalized sense, "harmful incident or event, hostile environment."
As "an exposure of the king to a direct attack from an opposing piece" early 15c. When his king is in check, a player's choices are severely limited. From that notion come the many extended senses: From the notion of "a sudden stoppage, hindrance, restraint" (1510s) comes that of "act or means of checking or restraining," also "means of detecting or exposing or preventing error; a check against forgery or alteration.
"Hence: "a counter-register as a token of ownership used to check against, and prevent, loss or theft" (as in hat check, etc.), 1812. Hence also the financial use for "written order for money drawn on a bank, money draft" (1798, often spelled cheque), which was probably influenced by exchequer. Hence also "mark put against names or items on a list indicating they have been verified or otherwise examined" (by 1856).
From its use in chess the word has been widely transferred in French and English. In the sense-extension, the sb. and vb. have acted and reacted on each other, so that it is difficult to trace and exhibit the order in which special senses arose [OED]
Meaning "restaurant bill" is from 1869. Checking account is attested from 1897, American English. Blank check in the figurative sense is attested by 1849 (compare carte blanche). Checks and balances is from 1782, perhaps originally suggesting machinery.
Old English freo "exempt from; not in bondage, acting of one's own will," also "noble; joyful," from Proto-Germanic *friaz "beloved; not in bondage" (source also of Old Frisian fri, Old Saxon vri, Old High German vri, German frei, Dutch vrij, Gothic freis "free"), from PIE *priy-a- "dear, beloved," from root *pri- "to love."
The sense evolution from "to love" to "free" is perhaps from the terms "beloved" or "friend" being applied to the free members of one's clan (as opposed to slaves; compare Latin liberi, meaning both "free persons" and "children of a family"). For the older sense in Germanic, compare Gothic frijon "to love;" Old English freod "affection, friendship, peace," friga "love," friðu "peace;" Old Norse friðr "peace, personal security; love, friendship," German Friede "peace;" Old English freo "wife;" Old Norse Frigg, name of the wife of Odin, literally "beloved" or "loving;" Middle Low German vrien "to take to wife," Dutch vrijen, German freien "to woo."
Meaning "clear of obstruction" is from mid-13c.; sense of "unrestrained in movement" is from c. 1300; of animals, "loose, at liberty, wild," late 14c. Meaning "liberal, not parsimonious" is from c. 1300. Sense of "characterized by liberty of action or expression" is from 1630s; of art, etc., "not holding strictly to rule or form," from 1813. Of nations, "not subject to foreign rule or to despotism," recorded in English from late 14c. (Free world "non-communist nations" attested from 1950 on notion of "based on principles of civil liberty.") Sense of "given without cost" is 1580s, from notion of "free of cost."
Free even to the definition of freedom, "without any hindrance that does not arise out of his own constitution." [Emerson, "The American Scholar," 1837]
Free lunch, originally offered in bars to draw in customers, by 1850, American English. Free pass on railways, etc., attested by 1850. Free speech in Britain was used of a privilege in Parliament since the time of Henry VIII. In U.S., in reference to a civil right to expression, it became a prominent phrase in the debates over the Gag Rule (1836). Free enterprise recorded from 1832; free trade is from 1823; free market from 1630s. Free will is from early 13c. Free school is from late 15c. Free association in psychology is from 1899. Free love "sexual liberation" attested from 1822 (the doctrine itself is much older), American English. Free and easy "unrestrained" is from 1690s.