Emulator and Simulator
Emulator is a kind of interface that works similar to real device. It is a virtual device or system which give almost all the controls acts same as real device or system. This gives the basic idea of something that how the system or device works. Emulator takes the complete place of real device. It can replace hardware and software as well of the system and could act as real system. It provides the platform to see the application behavior and functionality of different software without any real time device. For example ADT Emulator which provide the same interface and features as android phone. You can install the application in computer and use it in the same way how you use in android mobile. It provides all the infrastructure for the android mobile in virtual way. The interface completely looks like android device.
Simulator is a kind of interface which provides the basic behavior of the device but without device we can’t use simulator as we use emulator. However we can install or uninstall applications using simulator to the device. Simulator provides the infrastructure for the device in virtual way and the same operation could be performed without using external device. If the real system is engaged and not be accessible then Simulator could be used to perform the other work as real device. For example x-code simulator is used of iOS devices and it work similarly as iOS device works but alone x-code can’t work without device, however emulator could be use as stand alone.