"a small, light, round, spongy cake made with eggs," usually eaten buttered and toasted, 1703, moofin, possibly from Low German muffen, plural of muffe "small cake;" or somehow connected with Old French moflet "soft, tender" (said of bread). The historical distinction of the muffin from the crumpet is not entirely clear and the subject is involved. In American English the word was extended to a sort of cup-shaped bun or cake (often with blueberries, chocolate chips, etc.); hence muffin top "waistline bulge over tight, low jeans" (by 2005), from resemblance to baked muffins from a tin. Muffin-man "street seller of muffins" is attested by 1754.
Why sit we mute, while early Traders throng
To hail the Morning with the Voice of Song?
Why sit we sad, when Lamps so fast decline,
And, but for Fog and Smoke, the Sun would shine?
Hark! the shrill Muffin-Man his Carol plies,
And Milk's melodious Treble rends the Skies,
Spar'd from the Synagogue, the Cloathsman's Throat,
At measur'd Pause, attempers every Note,
And Chairs-to-mend! with all is heard to join
Its long majestic Trill, and Harmony divine.
["The Black Bird and the Bull-Finch," 1777]
1838, American English, apparently originally the name of some kind of alcoholic drink, of unknown origin. It has joined that class of words (such as dingus, doohickey, gadget, gizmo, thingumabob) which are conjured up to supply names for items whose proper names are unknown or not recollected. Used at various periods for "money," "a professional tramp," "a muffin," "male genitalia," "a Chinese," "an Italian," "a woman who is neither your sister nor your mother," and "a foolish person in authority." Popularized in sense of "foolish person" by U.S. TV show "All in the Family" (1971-79), though this usage dates from 1905. In typography, by 1912 as a printer's term for ornament used in headline or with illustrations.
About 10:30 o'clock there was a snap of breaking metal, and the machine was stopped. It was discovered that the gilderfluke had come into contact with the dudad which operates the dingus on the diaphason, thereby letting the Johnson bar oscillate as it were between Alpha and Omega, thus preventing the dingbat from percolating the perihelion of the gazabo, and causing the dofunny on the parallelogram to drop into oblivion. [from an Illinois newspaper's account of a production delay caused by a Linotype machine breakdown, reprinted in Inland Printer, Chicago, February 1903]