Stilistics is the study of form and style in language expressions. The style of a text can be defined as the unique proper subset of the set of all possible characteristics of a text.

A literary genre can be seen as a subset of characteristics that is commonly recognised and agreed upon. It is commenly recognised a detective story should involve a crime and how it was solved, a love story should describe romantic relations between protagonists and the turmoils it can bring, an advertisement should promote some product, a fable should involve animals having human characteristics, etc.

Another characteristic is the size of a work. We can distinguish for example between a poster, a flyer, a pamphlet, an essay, a short story, a novel or a trilogy, to name but a few.

More at the sentence/paragraph level are two (relatively) well-defined mutually-exclusive categories of style: proze and poetry. The latter involves rhyme while the former does not.

Other possible characteristics at the paragraph level can be: the use of dialog, the description of scenes, the use of active or passive voice, the distribution of sentence lengths, the use of specific language registers etc.