"We are such stuff as ... are made on" (The Tempest) (6)
I believe the answer is:
dreams
(Other definitions for dreams that I've seen before include "Thoughts and visions during sleep" , "'We are such stuff / As dreams are made on' (The Tempest)" , "Imaginings" , "'''We are such stuff as ... are made on'' The Tempest (6)'" , "Fantasies; fantasises" .)