Real LIfe Parent-Child Dialogue

Me, reading from Gerald McDermott's (wonderful) children's book, Papagayo: The Mischief Maker: "...the moon was now just a slender crescent."

Joseph, interrupting and pointing at the picture: "No! It's a waning gibbous!"

...This would be a perfect story had he been correct; sadly, honesty compels me to note that, alas, as best as I can tell he was mistaken. Nevertheless, in all honesty, I don't think I could have come up with the phrase "waning gibbous" at all without a brain extension. Until now, that is: now I imagine I'll never forget it.