It started with an innocent question. She asked me why the announcer had referred to a player as a "nickel back."
"Well, on defense there's ordinarily four guys in the backfield, which is what we call the players who cover the other team's receivers. In situations where they figure the other team is going to pass the ball, they'll often add a fifth guy to the backfield. That's called a 'nickel' defense, and we call him the 'nickel' back. Five...nickel...get it?"
She got it.
"So a 'dime' defense is 10 players in the backfield?"
"No, no, they never play 10. A 'dime' defense is 6 guys. And a 'quarter' defense is 7 defensive backs."
"That makes no sense."
No, I suppose it doesn't. "So anyway, the sixth guy is called the 'dime back.'"
"Right. And the seventh guy is called the 'quarter back.'"
"No, he's only on offense. The seventh guy is just called the seventh defensive back."
"The nickel and dime backs are on defense, but the quarterback's just on offense?"
"Right. Entirely different position."
"That makes no sense. The quarterback's not in the backfield?"
"Yes, but he's in the offensive backfield, with the halfback and the fullback."
She sighed. I braced for the inevitable. "Is the halfback half as big as the fullback and twice the size of the quarterback?"
She's right. This makes no sense.