Rheumatism is the collective denomination for systemic diseases of the locomotor system with possible involvement of internal organs, or on the basis of primary diseases, in particular of infectious, metabolic, endocrinological, hematologic or neurological origin. Problems of nomenclature related to this definition are discussed and examined critically from the linguistic point of view. With the aid of examples the nomenclature of significant rheumatic diseases is discussed as regards the linguistic and characterizing suitability of current or recommended terminology.