an egg's age

A dated American slang phrase meaning a very long time — often used hyperbolically in casual conversation to suggest an eternity has passed. The logic of the idiom is the implied slowness or perceived endlessness of waiting for an egg to hatch or age. Primarily a 19th and early 20th century expression, now virtually extinct in natural speech. Occasionally turns up in period fiction or dialect writing as a marker of old-fashioned American vernacular.