If Genres are types, classes, or kinds of literature, art, music, etc., what to call the marks, signs, or formulas that identify a genre?
The literary-critical term is "conventions," which everyday speech might describe as
motifsMetaphorically, conventions might be considered the genes or DNA of a genre—the building blocks or pieces that assemble a whole text. For instance, the conventions of a crime, a locked room, a mysterious note, an attractive but elusive woman, and a detective (professional or amateur) might be considered the conventions of the mystery genre.
Not rules but expectations (which can be purposefully frustrated)Oxford English Dictionary
Convention: 9a. General agreement or consent, deliberate or implicit, as constituting the origin and foundation of any custom, institution, opinion, etc., or as embodied in any accepted usage, standard of behaviour, method of artistic treatment, or the like.
9b. In a bad sense: Accepted usage become artificial and formal, and felt to be repressive of the natural in conduct or art; conventionalism.
10a. A rule or practice based upon general consent, or accepted and upheld by society at large; an arbitrary rule or practice recognised as valid in any particular art or study; a conventionalism.
Definitions of convention on the Web:
Not rules but expectations (which can be purposefully frustrated)
One way we practice judgment is to measure our reactions to changes to our expectations.
Does a specimen or example fall short of expectations, or take us further?
If further, was that a good change or a bad change?
Knowledge of genres = yardsticks, standards of measurement
Standards do not equal rules. Standards can be bent, raised, lowered, varied to need.
adjective form: "conventional"
Definitions of conventional on the Web: