stock market is like normal market where as things (shares) buying & selling happening virtually than physically. stock market govers by SEBI where as other market dont have such bodies. in stock market buyers & sellers decides the price in secondary market. there is two types of market. 1. primary market 2.secodary market. in primary market company issue stock & secuirities for first time pubic subcription where as in secondary market pre-issued of stock available for traders.
SENSEX and NIFTY are indices that determine the strength and state of the current market.