Via Nordic larp, and ultimately from the (unavailable) 2019 knutepunkt book, a Nordic-focused larp design glossary:
Lot of interesting terms in there.
My favourite so far is
The author(s) of a larp. The person or group who defines the larp’s vision, world, workshop structure, characters, etc. A synonym for larp designer from an era before game studies terminology colonised larp discourse. Also, a person who creates larps.