Demonstrative pronoun "demonstrate" someone or something?

Quote: “Demonstrative pronouns demonstrate or point out someone or something: this, that, these, those. >This is his umbrella; that is your umbrella.”

I think those words only “point out.” Can I ask why they are called “demonstrative?”

Hi,

‘Demonstrative’ also suggests ‘showing’. When you say to someone: It is this picture that I want you to see, I am showing the picture to someone.

Alan

Got it, thanks Sir Alan.