Question

I have just switch to android development and came across this doubt. How is AVD different from emulator?

Answer 1

AVD : Android Virtual Device

Quoting from the Android Developer Site : Managing Virtual Devices

An Android Virtual Device (AVD) is an emulator configuration that lets
you model an actual device by defining hardware and software options
to be emulated by the Android Emulator.

This itself means AVD and emulator are different. ie, AVD is an emulator configuration. Again, AVD is a configuration that runs on Android Emulator

Android Emulator

Now we need a explanation for Android Emulator. Again quoting from developer site. Using the Android Emulator

The Android SDK includes a virtual mobile device emulator that runs on
your computer. The emulator lets you prototype, develop and test
Android applications without using a physical device.

The Android emulator mimics all of the hardware and software features
of a typical mobile device, except that it cannot place actual phone
calls. It provides a variety of navigation and control keys, which you
can “press” using your mouse or keyboard to generate events for your
application. It also provides a screen in which your application is
displayed, together with any other active Android applications.

To let you model and test your application more easily, the emulator
utilizes Android Virtual Device (AVD) configurations. AVDs let you
define certain hardware aspects of your emulated phone and allow you
to create many configurations to test many Android platforms and
hardware permutations. Once your application is running on the
emulator, it can use the services of the Android platform to invoke
other applications, access the network, play audio and video, store
and retrieve data, notify the user, and render graphical transitions
and themes.

Note the BOLD sentence in above quote. It clearly mentions that, Android Emulator utilizes AVD configurations.