Hello Ajay,
I am not sure if there is an official definition but in general, since a packet is a unit of data that can refer to both a datagram (the IP unit of data) and to a frame (an ethernet or in general a layer 1/2 unit of data), I tend to refer to packetswitching when talking of processing of packet based on layer 2 addresses and packet forwarding when based on layer 3 (routing).
I saw it used even in term of the technology used: packet switching when the decision happens in (dedicated) hardware, like the ASIC of a switch and forwarding when it is done by software (although nowadays routers do a lot in accelerated hardware with tecnologies like DCEF).
Not sure if this helps or confuses the matte more ....
Cheers
Fabio
