This is how that conversation turned out:
Friend: Siri, find us a healthy restaurant.
Siri: I'm sorry, can you please define that?
Me: Ok, that's not going to work. We need to think of food genres.
Me: What's the word? Ethnicities?
Friend: Types? Categories? This feels like a bad game. I can't seem to think of it. What is the word?
.... <We both think about this for a while>
Friend: Maybe we should stop trying to think of the word and actually think of a characterization.
Me: Characterization? That's not it either. Ok, um...something Asian?
Friend: Siri, find a Japanese restaurant.
Siri: I found a few a little ways away.
Friend: That is so vague. What does that mean?
Me: I have no idea. Wait, how many Japanese people are there here anyway? Siri, how many Japanese people are there in Salt Lake City?
Siri: Let me think for a moment. The answer is 480.
<My friend and I laugh> <We ask about various populations for a few minutes>
Friend: We have to think about food!
Me: Middle Eastern! That's healthy and it includes vegetables and protein.
Friend: Good call.
Where did we end up going? An Ethiopian restaurant we came across on our way to the Middle Eastern restaurant. It was great.
But I still have no idea what food classification is called. Any takers?