Full Definition of INCISION1 a : cut, gash; specifically : a wound made especially in surgery by incising the body b : a marginal notch (as in a leaf) 2 : an act of incising something 3 : the quality or state of being incisive See incision defined for English-language learners See incision defined for kids Examples of INCISION<the surgeon made a thin incision with the scalpel>