Well, first there was (and there is, and always will be) Amitabh Bachchan. And now, 35 years after his superstardom started, there are Amitabh Bhattacharya and Amitabh Varma and maybe more coming up in the industry. But then, even today people ask what the word Amitabh mean. So here I give the answer, once again.
Amitabh is made up of two words, Amit + Abha. Amit means one that never dies and Abha is a glow, a radiance, maybe a halo. Hence, Amitabh means someone with a radiance that never dies. A person with an immortal glow.
By the way, the name Amitabh was given to the Mr Bachchan by renowned Hindi poet Sumitra Nandan Pant.