Today we are going to tackle some terminology.
First off, the terms font and typeface do not mean the same thing.
A typeface is a series of letters, numbers, punctuation and symbols which have a specific design. So contrary to what your computer software will likely tell you, when you select Calibri or Helvetica, you have not selected a font, but a typeface.
A font then is the means used to create a typeface. Today this often means a little piece of computer code that pops the letters up on screen, but it could also anything from stencils to stamps to old letterpress blocks.
The way I learned this difference to view the font as being a cookie cutter and the typeface as the cookie which is produced.*
Ultimately, the difference is insignificant enough (and the terms used interchangeably enough) that keeping this straight has become relatively unimportant, but every once-and-awhile you’ll run into an old-school designer who will insist upon them being used properly.
* I believe this description originated in James Felici’s book Complete Manual of Typography.