?What?s in a name? That which we call a rose By any other name would smell as sweet.? From ?Romeo and Juliet?, William Shakespeare (1594) This article opens a series of publications on disambiguation of the basic terms used in the field of intrinsically disordered proteins. We start from the beginning, namely from the explanation of what the expression ?intrinsically disordered protein? actually means and why this particular term has been chosen as the common denominator for this class of proteins characterized by broad structural, dynamic and functional characteristics.