in writing, to indicate the common casual pronunciation of could have, by 1909.
"financial losses, the debit side of an account," 1929, from the red ink traditionally used to indicate debits in accounts. Earlier, "cheap wine" (1919).
"principal street of a (U.S.) town," 1810, from main (adj.) + street. Used allusively to indicate "mediocrity, small-town materialism" from late 19c., a sense reinforced by the publication of Sinclair Lewis's novel "Main Street" (1920).
But a village in a country which is taking pains to become altogether standardized and pure, which aspires to succeed Victorian England as the chief mediocrity of the world, is no longer merely provincial, no longer downy and restful in its leaf-shadowed ignorance. It is a force seeking to dominate the earth, to drain the hills and sea of color, to set Dante at boosting Gopher Prairie, and to dress the high gods in Klassy Kollege Klothes. Sure of itself, it bullies other civilizations, as a traveling salesman in a brown derby conquers the wisdom of China and tacks advertisements of cigarettes over arches for centuries dedicate to the sayings of Confucius. ["Main Street"]
The motto is often translated as "He (God) is favorable to our undertakings," but this is not the only possible translation. Thomson wrote: "The pyramid signifies Strength and Duration: The Eye over it & Motto allude to the many signal interpositions of providence in favour of the American cause." The original design (by William Barton) showed the pyramid and the motto Deo Favente Perennis "God favoring through the years."
The Latin elements are the perfective of annuere "indicate approval, agree to, grant," literally "nod to (as a sign)" (from assimilated form of ad "to;" see ad-, + nuere "to nod;" see numinous) + perfect passive of coeptus, past participle of coepere "to begin, commence."
1707 as a direct phrase, but implied much earlier, and Old Norse had bikkju-sonr. Abbreviated form SOB from 1918; form sumbitch attested in writing by 1969.
Abide þou þef malicious!
Biche-sone þou drawest amis
þou schalt abigge it ywis!
["Of Arthour & of Merlin," c. 1330]
"Probably the most common American vulgarity from about the middle of the eighteenth century to the middle of the twentieth" [Rawson].
Our maid-of-all-work in that department [indecency] is son-of-a-bitch, which seems as pale and ineffectual to a Slav or a Latin as fudge does to us. There is simply no lift in it, no shock, no sis-boom-ah. The dumbest policeman in Palermo thinks of a dozen better ones between breakfast and the noon whistle. [H.L. Mencken, "The American Language," 4th ed., 1936, p.317-8]
Elsewhere, complaining of the tepidity of the American vocabulary of profanity, Mencken writes that the toned-down form son-of-a-gun "is so lacking in punch that the Italians among us have borrowed it as a satirical name for an American: la sanemagogna is what they call him, and by it they indicate their contempt for his backwardness in the art that is one of their great glories."
It was in 1934 also that the New York Daily News, with commendable frankness, in reporting a hearing in Washington at which Senator Huey P. Long featured, forsook the old-time dashes and abbreviations and printed the complete epithet "son of a bitch." [Stanley Walker, "City Editor," 1934]