vengence is a feeling for revenge, revenge is the act.
They are the same, except, vengeance is something you feel and revenge is the plot you employ to get your vengeance.
They are extremely similar...I would have to say revenge involves injury and/or avenging with equal degree to the offense (Such as somebody steals your bike so you steal theirs). Vengeance is more like punishment in retaliation of an injury and/or offense. Plus I have always considered vengeance to be the extreme of the two...(Such as someone beats you up and you respond by killing them)...
some carry both within for life, to life and by life... never seen, so very discretely and discreetly as we watched in movies, they could be within circles, unsuspected... a loathe for planned attack just as the predators do in almost all movies...... that very ideology is predatory.... why 14, what the f U King 25, when you cannot wage a war now!