If you’re really into the fascinating, creative-yet-practical world of typography (like I completely admit to being) you may have come across these two words (Font and Typeface) and seen them used interchangeably. However there is a subtle distinction, albeit one that’s less clear since typography made the jump from cast metal letters for a printing press to the realm of digital font files.
Robby Ingebretsen, at his blog NerdPlusArt.com has a great little explanation with some interesting addendums hashing out the exact description and good analogies. Check it out: http://nerdplusart.com/type-terminology-smackdown/
Ingebretsen provides a great analogy using music: “A typeface is like a song and a font is like a recording. One is the definition, the other is an instance. One is a concept, the other a manifestation.”
To sum it up, here’s a quote added in an update on the post, that seems to be perhaps the clearest explanation:
“A typeface is a family of fonts (very often by the same designer). Within a typeface there will be fonts of varying weights or other variations. E.g., light, bold, semi-bold, condensed, italic, etc. Each such variation is a different font.”