emacs TECO /tee'koh/ /n.,v. obs./ 1. [originally an acronym for `[paper] Tape Editor and COrrector'; later, `Text Editor and COrrector'] /n./ A text editor developed at MIT and modified by just about everybody. With all the dialects included, TECO may have been the most prolific editor in use before EMACS, to which it was directly ancestral. Noted for its powerful programming-language-like features and its unspeakably hairy syntax. It is literally the case that every string of characters is a valid TECO program (though probably not a useful one); one common game used to be mentally working out what the TECO commands corresponding to human names did. In mid-1991, TECO is pretty much one with the dust of history, having been replaced in the affections of hackerdom by EMACS. Descendants of an early (and somewhat lobotomized) version adopted by DEC can still be found lurking on VMS and a couple of crufty PDP-11 operating systems, however, and ports of the more advanced MIT versions remain the focus of some antiquarian interest.