Font vs typeface, ascender, desender, X-height, finial … there’s a nice one-page guide to all the Typography terminology.
Become a typography nerd in under 10 minutes by Andrew Coyle
Has a good visual summary of all the major words used talking about type – the broad categories of fonts (Serif, San-serif etc), how letters combine (kerning) to the words describing parts of a character (ascender, finial, bowl etc).
The only extra we could add is mentioning monospace fonts like Courier New
Monospace or fixed fonts use the same horizontal space for each letter, just like manual typewriters. Fixed fonts are useful for code snippets and other situations where you want each character to be very clear and distinct – like passwords.