A lot of ink and bytespace has been spilled trying to define this term. I think it’s a legacy term, with no useful definition. Certain activities by that name have nothing in common, and certain activities that go by other names have a lot in common with some called role-playing.
My published designs and current work in progress are listed in the menu, so here’s a look into the past.
unnamed fantasy, 1987: the first of my many hacks of The Fantasy Trip, plus lots of drugs and wizardry
Bullshit-less (BSL), 1991-92: my first utterly off-the-reservation design, written in defiance of design and play conventions rather than trying to please them
Gray Magick, 1994: furious fantasy adventure; see My fantasy heartbreaker design work for discussion
a bag of hacks and scribbles, 1996-97: including an ambitious magic system in “Talisman” (working title only)
The Human Machine, 1999: my first design after I learned about the Threefold Model, deliberately character-centric, strongly influenced by Ghost in the Shell and Blade Runner – the scenario creation rules showed up later in The Sorcerer’s Soul
Fantasy for Real, 1999: a partner-design to THM, deliberately setting-centric, comedic and a bit cynical fantasy, strongly influenced by Jack Vance’s Dying Earth series and refining the “Talisman” magic