Microstory
From IFWiki
A term - as far as I know - first used by MIT during the creation of the never-ending-conversation. A microstory is the smallest particle of a work of interactive fiction. During the creation of a work of interactive fiction, story parts are connected to each other with links or commands (or possibly an at-random sequence). Every story part is a possible followup to another story part. These story parts are called "microstories."