Benevolent Dictator for Life
"Benevolent Dictator for Life" (abbreviated as "BDFL") is a common jocular title for a leader of a free software project (most often, though not always, for open source methodology-based projects), and it is used by Piga Software. Hamish Paul Wilson is the current BDFL of Piga Software as well as several of its projects. Graham Lawrence Wilson, is also the BDFL for several projects, largely based around the creation of game engines as per his position as technical director.
The term's meaning, beyond a joke, is that during a serious debate over a project's future, and no consensus is reached, then the "dictator" has the final say. This is an important managerial fail-safe for open source methodology projects and any project that contains group collaboration.