also clearinghouse, 1805, from clearing + house (n.). The original was established 1775 in London by the bankers for the adjustment of their mutual claims for checks and bills; later the word was extended to similar institutions.
CLEARING, is a method adopted by city bankers, for exchanging the drafts on each others houses, and settling the differences.—Thus at a stated hour in the afternoon, a clerk from each attends at the Clearing House, where he brings all the drafts on the other bankers, which have been paid into his house during the course of the day; and, having debited their different accounts with the articles which he has against them, he deposits them in their proper drawers, (a drawer being here allotted to each banker:) he then credits their accounts respectively, with the articles which they have against him, as found in his drawer. Balances are then struck on all the accounts, and the differences are transferred from one to another, until they are so wound up, that each clerk has only to settle with two or three others, which is done in cash, or Bank of England notes. [P. Kelly, "The Elements of Book-Keeping," London, 1805]
mid-14c., "make clear (an obscure subject) in the mind, explain, elucidate;" late 14c., "make clean, cleanse, purify; clarify (a liquid), remove what clouds or diminishes brightness or transparency;" also "prove innocent, vindicate;" of the weather, sea, sky, clouds, etc., "clear up, become fair or calm;" from clear (adj.). Related: Cleared; clearing.
Intransitive sense of "become free from murkiness" is from 1580s. Meaning "to free from obstructions" is from 1520s; that of "to free from entanglement" is from 1590s; that of "pass (an obstacle) without entanglement or collision" is from 1630s. Sense of "to remove (something) out of the way" is from 1670s; that of "to clear land of trees and underbrush" is from 1690s. Meaning "to leap clear over" is first attested 1791. Meaning "to gain (a sum of money) in clear profit" is from 1719. Meaning "get approval for (a proposal, etc.) from authority" is from 1944; meaning "establish as suitable for national security work" is from 1948.
To clear (one's) throat is from 1881; earlier clear (one's) voice (1701). To clear out "depart, leave" (1825), perhaps is from the notion of ships satisfying customs, harbor regulations, etc., then setting sail. To get clear of is from 1590s. To clear up is from 1620s of weather, 1690s as "make clear to the mind." Clear the deck (1802) is from sailing ships. Clear the air in the figurative sense is from late 14c. To clear the coast (1520s) was to make it suitable for landing.
attention-getting interjection, c. 1600, lengthened from hem, which is imitative of clearing the throat.
early 13c., in place names, "a clearing, a forest glade," from Old French noun use of the adjective (see clear (adj.)). In Middle English also "a beautiful person" (mid-14c.). From c. 1500 as "brightness." The notion in in the clear (1715) is "a clear space."