union of two sets
The set of elements which are in at least one of the sets.
Ex: Let's say you are given the sets A={3,4,5} and B={4,5,6}, the union of the sets A and B, written A U B, would be {3,4,5,6}. Notice that there is no need to list the 4 and 5 twice.
zero
How about collective terms? Make up if can't find a proper one.
Ambush of tigers
