A term used in describing bugs or errors in software. When using two (or more) external libraries, api's or systems that operate against the same area of concern, it is possible that they will notplay well and cause very hard to trace errors.
jQuery and Angular.js both working against the same piece of the DOM. jQuery's cached version may not update in the rendered output because Angular has replaced the DOM object with another version, severing the connection that jQuery had. jQuery and Angular.js can cause Dueling Banjo's Syndrome.
An eggy banjo is a sandwhich which consists of soft bread or a bun filled with sausage or bacon and a over medium fried egg. Upon biting the sandwhich, the pressure of the bread and contents will squeeze the egg causing it to burst and squirt it's yolk down the shirt of the sandwich owner. This immediately causes the individual to raise the hand with the sandwich to approximately shoulder height whilst frantically trying to wipe away the yolk with the other. The resulting stance momentarily resembles that of a strumming banjo player... Hence the phrase "Eggy Banjo"