I'm looking for a word for when you have a collection A and a collection B and they have no overlap.
In mathematical terms: the relation between two sets where the intersection is empty. Like in this Venn diagram:
The word that keeps popping up in my mind is disparate sets, but I don't feel that completely covers the meaning when I look at the definition, because that doesn't seem to preclude overlapping sets that are different:
disparate 1. distinct in kind; essentially different; dissimilar: disparate ideas.