I can't believe the kids are forgetting this but
A crossover is when the cast of two canons get mixed together, either because Steve Harrington suddenly lives in a world where Tony Stark is avenging around or because there's been dimension hopping involved
A fusion is for when you take one cast of characters and a special attribute of the universe in a different canon (eg. Stranger Things but with daemons)
Now go forth and label your stories accurately, ya little punks ;)
















