Typeface vs font
A typeface is a style set of letters, numbers, and characters in a similar design. A font is a file with an individual style of a typeface. 'Inter' is a typeface. 'InterBold.ttf' or 'InterItalic.ttf' are fonts.
It is always more familiar and understandable to say 'Font.' It is the more common term. So it is not a problem if you call both typeface and a separate style file with the 'Font' word, especially if you are talking about typography with a client or someone who is not that involved in the nuances of design.
In this book, I almost always use the 'Font' word when referring to a font family or an individual file. It is easier that way. Sometimes I use the word 'Typeface' if I want to make a difference or to avoid repetition in the text.