Hybrid apps are those which mix the native languages with Web languages. in Firefox OS and Chrome OS the web is the native environment. There are no hybrid apps, just web apps.
I think it is common understanding that "Hybrid apps" are apps that run on the device, and are written with HTML, CSS and JS and leverage the device’s browser engine - not the browser - to render HTML and process the JavaScript.
PhoneGap/Cordova/appMobi apps are Hybrid apps.
Well, you could make an argument that Native Client is a hybrid approach, but in general I agree with you.