demonstration
B1Substantiv/US /dˌɛmənstrˈeɪʃən/ dĕm-ənstr-ĀSH-ən; UK /dˌɛmənstrˈeɪʃən/ dĕm-ənstr-ĀSH-ən/
The act of demonstrating; an exhibition; proof; especially, proof beyond the possibility of doubt; indubitable evidence, to the senses or reason.
