A colophon was originally “the inscription or device, sometimes pictorial or emblematic, formerly placed at the end of a book or manuscript, and containing the title, the scribe’s or printer’s name, date and place of printing” (Oxford English Dictionary).  A modern day example may be found in any Knopf book, where there’s also usually a description and history of the typeface used.

The word has tended to become synonymous with logo (deriving from logogram or logotype) standing for imprint: the devise and standard group of words identifying the publisher on the title page: in the case of Knopf again, the borzoi.

The word logotype goes back to hot metal days when each character was a separate piece of metal.  A logotype was originally a single piece of type metal containing a number of letters or a word.  Obviously if you tended always to put the same ID on your title page it saved time to set it up as a single piece which you’d just pull down whenever needed.  Strangely, a rigid application of this definition makes every line of Linotype officially a logotype.

Logogram refers back to the time of the scribes, who in order to save time and space used a number of logograms, the et of the Latin “and” being a prominent survivor in the shape of the ampersand.  Another example, @ for at, has recently gained a currency way beyond its earlier usage.  Other ligatures set on single piece of metal in hot metal days, and thus definable as logotypes, include ff, st, vr (for very) and the diphthongs ae, oe.