Vocab Lessons

I keep trying to teach Isaac new words. Recently we've been working on "tines" (the part of a fork) and "polymath" (someone's who's an expert in many different fields). Maybe I should aim a little lower, here's our conversation at dinner last night:

Me: Isaac do you remember what these are called [as I point to the tines on my fork]?
Isaac: No.
Me: Tines. This fork has four tines, I use them to poke my food.
Isaac: Oh.
Me: Do you remember what you call someone who knows a lot about lots of different things?
Isaac: No.
Me: A polymath. Polymaths know a lot about many different things.
Isaac: Oh.
Me, pointing to the tines again: Okay, what are these?
Isaac: Pokey-maths.
Me: Close enough, good work.
Isaac: Thanks, dad.