A fartleberry is of course one of those staccato type farts that has crusted over. Very much like a raspberry with attitude. Given suitable acoustic conditions it sounds much like a short burst from a sten gun or a pneumatic drill on a sharp frosty morning. Dictionaries have a habit of lagging behind popular usage, mine still says 'wicked' means bad/evil!

Even if you haven't seen a fartleberry, you must surely have heard at least one. Unless you mistook it for Concorde.