Even though business terms are not my forte,still let me help you out with them..
In India we have 2 very famous stock exchanges, one being even oldest in Asia
1. Bombay Stock Exchange = BSE
2. National Stock Exchange = NSE,
These financial institutions deal with share tradings,we have 30 companies (financially sound) in BSE and 50 companies in NSE .
When stocks for companies go up,we have Sensex going up and when Sensex goes down same does the stock.
Sensex is an index of stock amount up and down,and it is used in BSE ,the term Sensex (sensitivity index),was coined by Deepak Mohoni.
Also we have index at NSE - fifty companies = NIFTY !
You can find live stock feeds bse
Hope u got a bit about them,u should read about history of BSE ,wiki..its very interesting one...