A stock market or equity market is the aggregation of buyers and sellers (a loose network of economic transactions, not a physical facility or discrete entity) of stocks (shares); these are securities listed on a stock exchange as well as those only traded privately.
Key difference:
SENSEX is the stock market index for BSE Limited, previously known as the Bombay Stock Exchange.
SENSEX Index is comprised of 30 of the largest and most actively-traded stocks on the BSE. Nifty is the stock market index for the National Stock Exchange (NSE).
Nifty comprises of 50 of the largest and most actively traded stocks on the NSE that covers 22 sectors of the Indian economy.
Nifty is the stock market index for the National Stock Exchange (NSE). The NSE is another stock exchange which operates in India. NSE came into existence in 1991 by Government of India on the recommendation of the Pherwani Committee.
NSE is mutually owned by a set of leading financial institutions, banks, insurance companies and other financial intermediaries in India. Ownership and management operates separately in NSE. NSE covers segments like mutual funds, indices, exchange traded funds, equities, etc. of the capital market.