Agent noun of re-use; one who re-uses.

(computer games) A text-based online game in which players enter instructions on a command line to jointly engage in role-playing. MUDs are a precursor to the massively multiplayer online game.

(graphical user interface) A control created by a developer, usually by combining other controls, often intended for use in a specific application.

(computing) A set of users grouped together on a system for administrative purposes. / (computing) A community of users of a particular machine, operating system, etc.

(computing, dated) A graphic symbol defined by the user, replacing one of the text characters in the computer's character set.

(Wiktionary and WMF jargon) A simple, standardised box placed on a webpage to indicate the user's proficiencies or preferences.

Obsolete form of useful.

An island in the Baltic Sea on the border between Germany and Poland.

plural of userbox

plural of multi-user dungeon