Ionic vs Cordova: First of all I would recommend starting with Ionic because its better to have with some UI widgets to start with rather than a blank screen (Cordova) and to start from scratch.
Hybrid Apps:
These are not Native apps but rather use WebViews (browser built-in your app) to display your views (coded in HTML) and fetch user input and then use JavaScript (or Angular etc) to process them. Although they are not native but they have access to some of the Native APIs i.e. to take picture using camera, record video/audio etc.
Suggestion: If you want to develop native apps using a single code base use React Native, which uses HTML, JSX (JavaScript + XML) and CSS.