An Americanism recorded in 1843 and probably related to the old English expression in a crow's age meaning the same.
- (idiomatic, US, colloquial) A very long time.
- Jarn hasn't seen Schnie in a coon's age.
- We've been waiting a coon's age for our damn food.
- The word coon is a colloquialism for the North American raccoon.
- (colloquial: a long time): dog's age
- Encyclopedia of Word and Phrase Origins, Robert Hendrickson (Facts on File, New York, 1997), page 168.