Hello Rajesh,
about stacks or groups of switches the following terms are commonly used:
daisy-chain or daisy-chained: the switches are connected together using normal switch ports, the uplinks are shared by the switches.
cluster of swithes: a group of switches that are administered as if they were a single entity even if not chained.They share a management ip subnet.
stack of switches: stackable switches have special connectors and use special cables that allow them to interconnect their backplanes at high speeds (32 Gbps for C3750, 64 Gbps per C3870E)
the group is then administered as a single entity.
the topology is a ring and the stack is able to pretend to be a single device in STP towards outer world.
the first is not recommended
the second is older and useful only for management
real stacking is the third.
Hope to help
Giuseppe