Why do the terms digital and therefore digital computer seem to be so problematic? In all literature dealing with computer history, there is a certain indifference concerning the differently scaled function descriptions and terminologies of individual parts or the entire computer and its analogue, discreet or digital properties. “Digital” and “digital computer” was first used by George Robert Stibitz in 1942.” (Ceruzzi/Aspray 1990) So far, no author was able to state a direct source. In his closing report Report on electronic predictors for anti-aircraft fire control from 1942 about a computer-assisted anti-aircraft system Stibitz' pointed out the fundamental advantages of merely having to program and compute two discreet voltage levels.Based on this document, we can safely assume that the term “digital computer” was invented by Stibitz approximately three years before the completion of the first elec­tronic digital computers COLOSSUS and ENIAC. A sufficient prerequisite for the un­ambiguous property of the digital computer can only be defined negatively with Stibitz' elaborations: A digital computer does not have any analogue properties regarding in­terfaces and computing in any systemic scaling.