Despite many attempts, we do not yet know how to answer the question exhaustively and adequately: What is common Danish stød phonetically? Specifically, is there an underlying physiological constancy behind the considerable acoustic variability? And is there a common denominator to the different acoustic manifestations that might explain their perceptual equivalence? Systematic acoustic, physiological, and perceptual investigations of common Danish stød now span (a little more than) three quarters of a century. This is a review of that research, to determine what may be considered established phonetic facts about common Danish stød and the open questions that remain for future research.