A roguelike is a computer game that borrows some of the elements of another computer game, 1980's Rogue. A roguelike is a superficially two-dimensionaldungeon crawling computer game, usually with simple text or ASCII "graphics" and many with "tiles" which replace the rather limited character set with a wider array.
The genre is named after Rogue, although some features of Rogue existed in earlier games, notably: Adventure (1975), Dungeon (1975 for PDP-10 mainframes), and dnd (1975, written for the PLATO system on CDC computers). Unlike Rogue those games all had pre-scripted scenarios that were largely the same each time they were played and which players could grow tired of, with only some random variations. In Rogue the dungeon is randomly regenerated each time the player begins the game, creating a new challenge each time and remaining fresh for the player.
Becoming widely available with the Berkeley Software Distribution version of Unix, Rogue became the most popular dungeon crawl game yet created.