Typefaces and fonts aren't exactly the same thing. Sure, you may find others (or yourself) using these two words interchangeably, but there actually is a difference. These two words are very important when working with your designs or brandings, so it's important to know the difference to be more accurate in conversations with clients, co-workers, et cetera.

Typefaces

A typeface is a set of designs for letters and characters that vary can in size, width, height, spacing, style, and more. Typefaces are categorized by their style—the most popular are serif, sans-serif, and script.

Fonts

A font is the actual variation in size, weight, etc. of a typeface. For example, if a typeface is bold, italicized, extended, or any other variation, that's a font.

Font Families

Font families are groups of related fonts in a typeface. For example, Roboto is its own typeface, with its own fonts inside of it (including weights, widths, etc.) This collection of fonts is called a font family.