In early editions of the game these publications were commonly referred to as modules, which stems from the term dungeon module, used to refer to the earliest adventures published by TSR, with other variations on the module name appearing on latter adventures. The term module continued to be popular among players of the original Dungeons & Dragons and Advanced Dungeons & Dragons even after newer publications were labeled adventure. Adventures that appear as a part of a larger accessory are often referred to as scenarios.
The exact differences between the terms adventure, module, scenario, and accessory are hard to precisely define in Dungeons & Dragons terminology, as they all have been used in different ways.
The first published Dungeons & Dragons scenario was "Temple of the Frog", included in 1975's Blackmoor Dungeons & Dragons rules supplement. This scenario was later developed into the stand-alone module DA2 – Temple of the Frog for the D&D Expert set rules (TSR, 1986).
The first stand-alone Dungeons & Dragons adventure module, Palace of the Vampire Queen, was published in 1976 by Wee Warriors. Although TSR did not produce this module, the company did distribute the first three printings on behalf of Wee Warriors. The adventure was described as a "Dungeon Masters Kit" rather than a "module" or an "adventure".
Also in 1976, the adventure Lost Caverns of Tsojconth was distributed by Metro Detroit Gamers as the tournament module for the gaming convention Wintercon V, but was not published for general distribution at the time. The adventure was later re-written for the first edition Advanced Dungeons & Dragons rules and published as module S4 – The Lost Caverns of Tsojcanth (TSR, 1982).