Is there any difference between DIO and port because in some documents i am finding different specifications for DIO (digital input and output) and Port? Please advise.

 

Same difference.
Give us examples that are causing confusion.

 

The port (there are several types of ports like PMP,SPI,DIO(with PORT/LAT), etc ...) register is a memory mapped address(s) while DIO is a possible configuration of the hardware accessed at the address and/or pin(s).

With things like PPS the separation of location and operation becomes more configurable.

 

Could it be that DIO is digital only and PORT/GPIO can digital or analog?

 

I normally think of a port as being made up of more than one data I/O pin of similar function.