Such apps are developed for a single mobile operating system exclusively, therefore they are “native” for a particular platform or device. App built for systems like iOS, Android, Windows phone, Symbian, Blackberry cannot be used on a platform other than their own. In other words, you won’t be able to use Android app on iPhone.
Main advantage of native apps is high performance and ensuring good user experience as developers use native device UI. Moreover, an access to wide range of APIs that puts no limitation on app usage. Native applications are distinctly accessible from app stores of their kind and have the clear tendency to reach target customers.
Some cons to native apps are higher cost compared to other types of apps – due to the need of creating app duplicates for other platforms, separate support and maintenance for different types of apps resulting in bigger product price.