Dictionary.net

(XOR, EOR) /X or, E or/ A two-input Boolean logicfunction whose result is true if one input is true and theother is false. The truth table isA | B | A xor B--+---+--------F | F | FF | T | TT | F | TT | T | FThe output is thus true if the inputs are not equal. If oneinput is false, the other is passed unchanged whereas if oneinput is true, the other is inverted.In Boolean algebra, exclusive or is often written as a plus ina circle: "⊕". The circle may be omitted suggestingaddition modulo two.In digital logic, an exclusive or logic gate is drawn likea normal inclusive or gate but with a curved line acrossboth inputs:exclusive or gate (img:http://upload.wikimedia.org/wikipedia/commons/e/e0/XOR.jpg).