This paper focuses on the complementarity within the lexical binomial style/expressivity during the 19th century. If style is a product, a cultural object, which represents social forms of individuation, expressivity is a linguistic property revealed by the polyphonic space of discourse ; it steers the realisation of semioses in the direction of a perceptible individualisation of linguistic forms. The discipline known as « stylistics », which emerges at the end of the 19th century, was a general science of morpho-discursive expression : its restriction to literary studies is one of the more regrettable misinterpretations of the 20th century.