Before understanding the components of a Solar Energy system, lets first take a look some terminology:
The solar (also referred to as Photovoltaic) cells are made from silicon and manufactured to capture sunlight and convert it to electricity. A more detailed explanation can be found here.
The modules contain many solar cells connected together and housed in a protective unit that can go on your roof and survive the elements.
We must string the Modules together to create a Solar Energy system, which combines all of the electricity produces and delivers it to the inverter and then to your home.
Basically a fancy name for your integrated and interconnected solar energy system.