until the cows come home

Etymology
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.

The phrase was first coined by in 1691 in his account of Ireland: in Teague Land: or A Merry Ramble to the Wild Irish (1698) he says “on Sundays and Holydays, all the people resorted with the piper and fiddler to the village green. Where the young folk dance till the cows come home", probably because the Irish would often bring their cows into their homes at night as mentioned by Dunton

Phrase

 * 1)  For a very long period of time.
 * 2) * 1952 March 10, Justice Felix Frankfurter (dissenting), Sacher v. United States 343 U.S. 1, Supreme Court of the United States, pages 69–70:
 * 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.
 * 1) * 1952 March 10, Justice Felix Frankfurter (dissenting), Sacher v. United States 343 U.S. 1, Supreme Court of the United States, pages 69–70:
 * 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.
 * 1) * 1952 March 10, Justice Felix Frankfurter (dissenting), Sacher v. United States 343 U.S. 1, Supreme Court of the United States, pages 69–70:
 * 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.
 * 1) * 1952 March 10, Justice Felix Frankfurter (dissenting), Sacher v. United States 343 U.S. 1, Supreme Court of the United States, pages 69–70:
 * 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.

Usage notes
The phrase is often used to describe activities regarded as futile or unproductive.

Translations

 * Dutch: tot sint-juttemis
 * Finnish: maailman tappiin asti
 * French: aussi longtemps qu'on veut
 * German:
 * Hungarian: ítéletnapig, sohanapjáig
 * Icelandic: fram í rauðan dauðann
 * Irish: go brách na bréithe
 * Latin: ad calendas graecas
 * Maori: ki konā
 * Polish:, ile wlezie