coon's age definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
Informal an indefinitely long time
Origin: fanciful and amp; emphatic ; from raccoon
coon's age definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A long time.
coon's age - Phrases/Idioms
Also, a dog's age. A very long time, as in I haven't seen Sam in a coon's age, or It's been a dog's age since I went to the ballpark. The first phrase rests on the mistaken idea that raccoons (“coons”) live a long time. The variant may reflect a similar assumption but the true origin is not known. [c. 1835] Also see donkey's years.