A long time ago, a typeface called Century was devised by ATF for Century Magazine.
Later, that typeface was used as the basis for the very popular Century Expanded typeface from ATF. And then numerous other typefaces were added to the family. Century Oldstyle, a modern descendant of Alexander Phemister's old style typeface. Century Schoolbook, which was very popular in the 1960s.
Century was quite narrow; Century Expanded, although still somewhat narrow, thus providing economy of space, was a conventional typeface. Century Schoolbook was not narrow at all, but it seems to me to be just a tad too Clarendon-ish to be the ideal typeface for general text typography.
So I would have liked to find a Century Wide, as it were - and I thought I did run across such a face with such a name, somewhere in a specimen book, but I couldn't find it again. Of course, what with optical scaling, Century Six would do, were there such a thing.
A while back, looking through a specimen book of IBM Selectric Composer typefaces, I saw that the typeface that they simply called Century was similar to Century Expanded in styling, but to Century Schoolbook in width. Thus, it wasn't what was just called Century in ATF specimen books.
An understandable misnomer - since they had just one style from the Century family, why not give it an unmodified name. But using a different name does cause confusion, and it does obscure the history of the face, so I still deplored it a bit, even though I liked the face, it being the version of Century I wanted.
But just today, I've found out that IBM was not alone in this.
ITC Century, it turns out, from the catalogue of the original batch of ITC typefaces in issue 1, volume 8 of U&lc magazine, is another "Century" that follows IBM's naming convention.