The width of a font specifies the compression or expansion of the font. Arranged from narrowest to widest (more or less):
ultra compressed, extra condensed, compressed, condensed, narrow regular semiextended, extended, expanded, wide
Expansion or compression of fonts is sometimes done automatically (as by
scale operator), and sometimes done by humans. In
the latter case, the human will also presumably choose a font name which
includes ‘Extended’ or ‘Expanded’ or ‘Condensed’ or ‘Narrow’ or whatever
according to their own preferences; the abbreviation can follow along.
When creating a new synthetically expanded or compressed font for use
with TeX, e.g., with Afm2tfm or
fontinst, use ‘n’ and
Here is the table, from the file width.map. It is organized alphabetically by abbreviation. Each line consists of an abbreviation and any parts of a PostScript ‘FontName’ which use that abbreviation.
c Condensed Cond e Expanded n Narrow Semicondensed o UltraCondensed p Compressed Compact q ExtraCompressed ExtraCondensed r Normal Medium Regular (usually omitted) t Thin u UltraCompressed v ExtraExpanded more than Expanded, less than Wide w Wide x Extended Elongated y Semiexpanded