What is the origin of the term 'til the cows come home? While discussing this with friends tonight, the group had two possible explanations:
Cows return to their barn for milking at a given time late each night.
If a cow runs away or escapes, it doesn't return, unlike horses, which will return to their stable. As such, 'til the cows come home is an indefinitely long time.
So, which is correct? If anybody can point me to a reputable source explaining the history of this phrase, I'd be interested to know.