until the cows come home

Possibly from the fact that cattle let out to pasture may be only expected to return for milking the next morning; thus, for example, a party that goes on “until the cows come home” is a very long one. Alternatively, the phrase may have a Scottish origin, and may derive from the fact that cattle in the Highlands are put out to graze on the common where grass is plentiful. They stay out for months before scarcity of food causes them to find their way home in the autumn for feeding.

• "You can crank the engine until the cows come home, but it won’t start without fuel."
• "Good Morrow, / Drinke tell the Cow come home, 'tis all pay'd boyes."
• "If there be any lazy Fellow, any that cannot away with Work, any that would wallow in Pleaſures, he is haſty to be prieſted. And, when he is made one, and hath gotten a Benefice, he conſorts with his Neighbour Prieſts, who are altogether given to Pleaſures; and then both he, and they, live, not like Chriſtians, but like Epicures; drinking, eating, feaſting, and revelling, till the Cow come Home, as the saying is; [...]"
• "Come my brave Man of War, trace out thy darling, / As you my learned Council, ſit and turn boyes, / Kiſs till the Cow come home, kiſs cloſe, kiſs cloſe knaves. / My Modern Poet, thou ſhalt kiſs in couplets."
• "Miſs, if I had ſaid ſo, I ſhould have told a Fib; I warrant you lay a Bed till the Cows came home: But, Miſs, ſhall I cut you a little Cruſt now my Hand is in?"
• "If the Duke [Arthur Wellesley, 1st Duke of Wellington] will but do what he unquestionably can do, and propose a Catholic Bill with securities, he may be Minister [in Robert Peel's cabinet], as they say in Scotland "until the cows come home.""
• "Now I can't stop lawyers from calling me names and saying I am guilty of judicial misconduct and that I am prejudiced, and this, that and the other thing, and you can keep that up until the cows come home; that is all right, and I take no umbrage at it."
• "Middleton, up to that time, July 1952, had been prepared to give the lovable old gentleman the benefit of every possible doubt and talk to him until the cows had come home and gone to bed."
• "But I could quote from Animal Warmth and Up On All Fours until the cows come home. I could quote until the cows came home about the cows not coming home."
• "She could list Buck's good qualities from now until the cows came home. If the cows came home. If she waited for him to return until the cows came home, she'd never see any of them again."
• "John [Carradine] and I became quite close, we worked in several movies together. He could recite Shakespeare ’til the cows came home [laughs], and he had a heart as big as outdoors."
• "Anders and his wife had bought a house in an exclusive Cincinnati community where they'd partied with the wealthy elite, "hobnobbing" until the cows had come home."

• a cold day in hell
• at latter Lammas
• donkey's years
• that'll be the day
• until one is blue in the face
• when hell freezes over
• when pigs fly