clojure.set/union

(clojure.set/union) (clojure.set/union s1 s2 ...)

Answers the members of every set: of none #{}, of one the set itself, otherwise the others' members conjoined onto the largest input, like the oracle (so nil inputs answer nil when every input is empty). Reached also as alias/var or a referred bare union; works as a function value too.