Some typeface names are humorous — even if they were not intended to be so — like “Zapf,” “Friz Quadrata,” “Bodoni Bold” and “Harry Heavy.”
Sometimes “font” is used for a very specific typeface description like “24 point Century Gothic bold italic.”
[above] “Letterform” may mean the basic shape of a character, regardless of the typeface. You could say that “the letterform of a zero is oval.” Almost every version of the uppercase “A” has the same letterform: two converging vertical (or almost vertical) lines with a crossbar.
[above] The farther a letterform evolves from its traditional shape, the more likely it is to be unrecognizable, or confused with another letter.
This material is adapted from my upcoming No More Ugly Books!