Can anyone help me,
Why Op Amp is called "Operational Amplifier" ?
Is Instrumentation Amplifier is not Operational Amplifier?
Please explain in your own words.
Thanks,
Why Op Amp is Operational Amplifirer?

Op Amp is abbreviation of operational amplifier, which means performing some mathematical operations on input signal and performing amplification i.e. adding or subtracting two signals and amplifying their result just as in mixer circuits etc.
Until my info, all instrumentation amplifier contains op-amps as basic building blocks just like logic gates in digital circuits. And the differential amplifier is the basic building block of op-amps. So, the instrumentation amplifier generally contains op-amp circuits to create specialized amplifier modified/tailored for particular application like audio amplifier, RF amplifier etc.
Thanks
By the way I will Recommend:
[url=http://www.theengineeringprojects.com/2015/05/operational-amplifier.html]Operational Amplifier