The Silk Road was the name given to a number of various routes which traversed the countries between the East and West, quite often via the Indian Ocean. The purpose of these routes was to facilitate trade between the East and the West and allow traders to transport and sell their wares in the most efficient manner. These routes have existed since the time of ancient civilisations: for example, the Chinese developed silk production around 2700 BC and began to export it to the Romans shortly after.
Interestingly, the name 'Silk Road' was only invented in the 19th century - contemporary traders did not use any particular names for the trade routes they used. This name was invented by a German geologist called Baron Ferdinand Von Richthofen.