1963 M. Moorcock SF Adventures (May) № 3: Within it there were many things, many intelligences who did not realise they dwelt in a multiverse since, within itself, it was comprised of many universes, each one separated from the other by dimensions, like leaves between the layers.
1987 N. Spinrad Little Heroes (1989) № 150: How many times had she experienced such a magic moment of reality transformation from on high as the LSD [...] began its rush through her brain, as ordinary earth-bound reality dissolved into the multiverse of the infinite possible, taking her spirit with it?
1990 New Scientist (June 9) № 37/2: The wormhole picture changes our view of the "origin" of the Universe in a big bang, which is now seen simply as the event corresponding to our Universe branching off from the greater "multiverse."
1996 Interzone (Mar.) № 44/1: I used to be a citizen of the world, but now I'm a citizen of the multiverse.
2001 Dreamwatch (Mar.) № 90/4: A battle below threatens the fabric of the multiverse, a battle directed by Gaynor and at the very heart of his family's destiny.
2005 K. Baker Rick Bowes: Appreciation R. Bowes From Files of Time Rangers № xii: The Time Rangers themselves are mortals recruited from across a multiverse of war-torn worlds, stationed in decades as other mortals live in neighborhoods.