When does a joke become a dad joke?
When it's fully groan.

When a man becomes a dad, he takes on certain responsibilities: providing for his family, raising up his children to be good citizens--and telling the absolute worst jokes he can come up with.

But dad jokes don't always come naturally, which is why Sandy Silverthorne created The Best Worst Dad Jokes. Filled with more than 500 groan-worthy jokes to torment your kids, this collection makes it possible for you to fill any moment of dead air with a joke that will have everyone within hearing distance rolling their eyes and edging away to avoid association with you. Jokes like . . .

I don't have a dad bod; I have a father figure.

I saw a sign that said "Watch for Children," and I thought that sounded like a fair trade.

and

What does a baby computer call its father? Data!

And, hey, it's only downhill from there.