I absolutely hate this sort of pedantry. This is fine if your'e sitting around joking around with your fellow designer friends, but I see this used all the time to try and make people feel bad about themselves because they're "stupid".
And actually, "what font did you use" is correct you arrogant jackass, at least using the definition that you gave. Or are you designing PDFs using a letterpress?
I wonder if there is anything that feels this pedantic when I'm trying to carefully explain it to someone else. This is such a useless distinction in my mind.
Alas.. someone somewhere is calling their computer a hard drive and that would cause me to shudder. :)
In strict terms, a font is not a font at all. The word is erroneous in spelling. A "fount" would be the correct terminology; somewhere along the way (probably because of mispronunciation), the spelling was changed.
If he's going to go full pedant on this, he might as well disregard the word altogether.
"In typography, a font (also fount) is traditionally defined as a quantity of sorts composing a complete character set of a single size and style of a particular typeface."
Why is this important? Now that typefaces are embedded in the web we'll see the typography become more and more sophisticated. So it's important for techies to really learn the language of typography. Also since we're seeing amazing advances in screen resolution we can really start to show several weights of a typeface at a very small size.
In fact my bet is that as we see resolution increase we'll start to embrace vastly improved typography. In the old days the cut of a typeface at 72 points was different than the same typeface at 12 points -- so the typeface wasn't just auto-scaling up and down in size by stretching it. My bet is that we'll see a real revolution in the next few years in this area.
A better phrasing was used by someone on a panel at SXSW (Frank Chimero, perhaps? Jason Santa-Maria?). Anyway, they were conveying the idea that a font is a digital representation of a typeface, and they used this analogy:
Song : MP3 :: Typeface : Font
I agree, though, that making a big deal out of people getting it wrong is a sign of insecurity and pretentiousness.
In Polish the term for cast metal sort (czcionka) has become synonymous with both font and typeface.
I suspect the reason is the same as with font in English — it's the only term that Word (and its predecessors) used for everything font/typeface related.
Given that -- unless you're literally cutting and pasting things together -- you require a corresponding font to create something in a given typeface, I don't see any point in pedantically distinguishing between them.
And actually, "what font did you use" is correct you arrogant jackass, at least using the definition that you gave. Or are you designing PDFs using a letterpress?