Verisimilitude - the 'respective realism' or 'internal logic' of a text
Media texts are not realistic. Even the simplest documentary has been edited, subjected to post-production techniques and has been presented in such a way as to present a compelling narrative. Soap operas such as Eastenders seems pretty 'realistic' as there are no aliens or exploding heads present, but there are several puzzling omissions. Why do none of the characters ever swear? Why are all of the beers in the pub unbranded? How can the characters afford to live in one of the trendiest, most expensive parts of London? Why does something dramatic happen exactly three times a week? The answer to these questions, of course, is always 'because it's a soap opera. Foul language and extreme violence may be perfectly acceptable in a Tarantino film, but not in a family orientated soap opera.
So each genre and text has it's own set of rules that makes it 'realistic' on it's own terms. We can call this verisimilitude, which is Latin for 'like the truth'. Producers try very hard to establish verisimilitude in texts, and audiences can be left puzzled if a text breaks it's own verisimilitude. For example, in Indiana Jones and the Crystal Skull (Spielberg, 2008), we see Indie surviving direct impact by an atomic blast by climbing into a fridge. While the series has seen many supernatural and ridiculous elements, this scene breaks every notion of logic, and pushes the audience so far out of the diegesis that the verisimilitude is broken. Now 'nuking the fridge' is used as shorthand for when a film completely smashes it's own internal logic!
Despite it looking pretty fearsome (and tricky to spell!), using verisimilitude in a written piece is not too tricky. Here are a few generic sample sentences:
"The use of diegetic sound here establishes verisimilitude..."
"The director here deliberately breaks the verisimilitude of the gangster genre for comic effect..."
"By using generic paradigms typical of sci-fi, the producer clearly constructs an otherworldly narrative while still maintaining a sense of verisimilitude"
Further reading
This short presentation further elaborates on the notion of verisimilitude, using the example of the Star Wars franchise, which while being fundamentally 'unrealistic', clearly has its own set of rules that it sticks to.