User281315223 posted
Native IOS and Android is going to refer to experience in writing "native" applications for those platforms (ie writing a non-web application that targets those specific platforms).
For instance, if you were going to
write a native IOS application, you would probably write it in Objective-C along using XCode whereas if you were going to
write an Android application using Eclipse and the associated tools for developing Android applications.
Consider Xamarin
If you are familar with .NET, you might want to consider checking out
Xamarin.
There isn't going to be any completely universal application that is going to work across all devices and environments in a "native" application sense. Each application is going to require its own development to target details specific to each device
(for instance iOS, Android, Windows Phone will all be different environments and would all require their own applications).
I would highly recommend looking into Xamarin and some of their products, which are specifically geared for developing native iOS, Android, and Windows Mobile applications using C# (so the transition would be very minor and you
wouldn't have to go learn Objective-C etc.)
I have used them in the past to develop some iOS "Apps" and I was more than impressed with how easy their tools were to use and how smooth the transition was from working in something like Visual Studio to Xamarin Studio (their IDE). Depending
on your Application and what it does, you may also consider looking into PhoneGap, which aims at creating applications in a cross-platform way that can be installed on Android, iOS and other devices.
