hello friends .. i know my title is a bit big..but i just want to know about the exact meaning of the various movie genres mentioned and the difference between them even if its a minute one, i wanna know:

Action
Mystery
Thriller
Horror
Suspense
Gore
Adventure

The genre of suspense and gore isn't mentioned at imdb but still for more precision i added it so if there's any slight difference i would come to know..
and i would also like to know why in film titles these are written together like at imdb even if these genres are different ??