What is stock market?

Stock Market is specific place for Trading Companies Shares and public can purchase or sell the share and every country regulate stock market with rules and regulation.  

What is Companies share?

Companies share mean most of big business like cement factory, Commercial Banks etc are need to Heavy Capital / Investment for establish in this situation Government allow to business man with rules and regulations regulated by Securities and exchange commission Pakistan to launch share in the stock market for again Capital.

For example:
 If any business man wants to gain capital and he fulfill all requirement of Security Exchange of Pakistan for cement factory or need investment for said per is required 1 billion then he launch 10 million shares in the market and price Rs. 100 per share after the sold of  Shares then buyer can sell and buyer can purchase easily and determind the market price in the stock market.