The article is dedicated to the speech genre as a unifying basis for different theories of style. We clarify the notions of language, speech, dis-course, text in terms of «language phenomena» aspects singled out by L. V. Scherba. Terminological stability allows us to outline four approaches to style definition: cognitive, systemic-structural, textual and communicative. The cognitive aspect of style corresponds to the «system of concepts and strategies of usage». In this view, the speech genre allows for diverse definitions.