Meaning "to reckon for money given or received, render a reckoning," is from late 14c. Sense of "to explain, justify" (c. 1300) is from notion of "present a detailed explanation of money, etc. held in trust." Transferred sense of "to value, to estimate" (to account as belonging to a certain class of quality) is from late 14c. Intransitive sense of "to render an account of particulars" is from late 14c.; hence transitive sense "give an explanation" (1670s, usually with to before a person and for before a thing).
In later Old French partly re-Latinized as acompter (Modern French accompter), hence late Middle English accompten. Related: Accounted; accounting.
figurative sense is attested from 1832, from profit-and-loss accounting, where the final figure calculated is the bottom line on the page. Also (especially as an adjective) bottom-line, bottomline.
Old English blæc "the color black," also "ink," from noun use of black (adj.). From late 14c. as "dark spot in the pupil of the eye." The meaning "dark-skinned person, African" is from 1620s (perhaps late 13c., and blackamoor is from 1540s). Meaning "black clothing" (especially when worn in mourning) is from c. 1400.
To be in black-and-white, meaning in writing or in print, is from 1650s (white-and-black is from 1590s); the notion is of black characters on white paper. In the visual arts, "with no colors but black and white," it is by 1870 of sketches, 1883 of photographs. To be in the black (1922) is from the accounting practice of recording credits and balances in black ink.
For years it has been a common practice to use red ink instead of black in showing a loss or deficit on corporate books, but not until the heavy losses of 1921 did the contrast in colors come to have a widely understood meaning. [Saturday Evening Post, July 22, 1922]
Old English writan "to score, outline, draw the figure of," later "to set down in writing" (class I strong verb; past tense wrat, past participle writen), from Proto-Germanic *writan "tear, scratch" (source also of Old Frisian writa "to write," Old Saxon writan "to tear, scratch, write," Old Norse rita "write, scratch, outline," Old High German rizan "to write, scratch, tear," German reißen "to tear, pull, tug, sketch, draw, design"), outside connections doubtful.
For men use to write an evill turne in marble stone, but a good turne in the dust. [More, 1513]
Words for "write" in most Indo-European languages originally mean "carve, scratch, cut" (such as Latin scribere, Greek graphein, glyphein, Sanskrit rikh-); a few originally meant "paint" (Gothic meljan, Old Church Slavonic pisati, and most of the modern Slavic cognates). To write (something) off (1680s) originally was from accounting; figurative sense is recorded from 1889. Write-in "unlisted candidate" is recorded from 1932.
1610s, "a person's wealth," from Medieval Latin capitale "stock, property," noun use of neuter of Latin capitalis "capital, chief, first" (see capital (adj.)). From 1640s as "the wealth employed in carrying on a particular business," then, in a broader sense in political economy, "that part of the produce of industry which is available for further production" (1793).
[The term capital] made its first appearance in medieval Latin as an adjective capitalis (from caput, head) modifying the word pars, to designate the principal sum of a money loan. The principal part of a loan was contrasted with the "usury"—later called interest—the payment made to the lender in addition to the return of the sum lent. This usage, unknown to classical Latin, had become common by the thirteenth century and possibly had begun as early as 1100 A.D., in the first chartered towns of Europe. [Frank A. Fetter, "Reformulation of the Concepts of Capital and Income in Economics and Accounting," 1937, in "Capital, Interest, & Rent," 1977]
Also see cattle, and compare sense development of fee, and pecuniary. Middle English had chief money "principal fund" (mid-14c.). The noun use of the adjective in classical Latin meant "a capital crime."