From Fedora Project Wiki
A font family corresponds to one entry in GUI font lists. For example, DejaVu Sans, DejaVu Serif and DejaVu Sans Mono are three different font families.
A font family is subdivided in faces or styles. DejaVu Sans Normal, DejaVu Sans Bold, DejaVu Sans Condensed Italic are three faces of the DejaVu Sans font family.
The gnome-font-viewer command can be used to check the font family name and the font face/style declared by a font file. Notes: