n. 1 (foll. by of) a the outward showing of feeling etc. b an instance of this. 2 a public meeting, march, etc., for a political or moral purpose. 3 a the exhibiting or explaining of specimens or experiments as a method of esp. scientific teaching. b an instance of this. 4 proof provided by logic, argument, etc. 5 Mil. a show of military force. demonstrational adj.
[ ME f. OF demonstration or L demonstratio (as DEMONSTRATE) ]