Saying: "I build web applications" means nothing to them, and saying "I create website" makes you look like a wizard doing some black magic.
But saying "my job is to make websites accessible to everyone: we are used to use a screen and a mouse, but what if you are blind or deaf? Those people should not be allowed to go on any website? My role is to make those people able to browse the web, as you and me" give them an example of what kind of problems you actually solve as a web developer.