From IFWiki

A single complete progression through a variable text. For example, a player of Emily Short's "Galatea" will eventually run out of story, and the game will end; the player has fully traversed a path through the text. But "Galatea" offers dozens of these paths. The complexity of the game's structure begins to emerge only after the player returns to the beginning and attempts different actions. (See also rail game, replayability, session.)

-- DGJ 06 Sep 2002