Call me slow or dim-witted, but I always thought "no" summed it up pretty clearly.
I'm a sort of an old-fashioned, Oxford English Dictionary kind of guy. “No” means no. As in no, you can't eat more candy, take the car out for a spin on your 13th birthday, or sell your new brother Zak on eBay.
But that's me.
In the kid dictionary, “no” means “maybe, possibly, depends, wait 5 minutes and ask again.”
And here we have the great parental debate: What do we do with a no.