Genre

Genre is a type of media product. 

Film
horror
comedy
romance
drama
thriller
sci-fi
documentary
supernatural
slasher
romcom
coming of age
children
animated
action
adventure
fantasy
indie
non-fiction
horror-comedy
parody
satire
historical
war
musical
crime
period
anime
western

Music
pop
rb
drill
rap
classic
ballads
rock
metal
grind
house
alt
country
jazz
edm
acid house
metal
punk rock
indie
musical theatre
thme tune
soundtrack
backing track
synth wave
electro-swing
lofi
vapourwave
dubstep
reggae
latin
opera
raggaeton

Generic-fluidity is the way in which a genre changes over time.

Sub-genre is a genre within a genre, the notions of subgenre and generic hybridity are arguably more important than traditional genres. 

Genre paradigms make up genres and allow the audience to immediately recognise the genre, also known as genre conventions. Iconography is the familiar signs of the genre, such as a cowboy hat for a western movie.

Steve Neale, theories around genre
Key theory 3

Genre is repetition and difference over and over. Texts need to conform

Genre exists to attract a psychographic who want familiarity from codes and conventions, producers needing a sure-fire successful film benefit greatly from it as they know what an audience will want to watch. Likewise, audiences will be able to differentiate between films, knowing what fits their taste.