Mark Twain once divided the world into two kinds of people: those who have seen the famous Indian monument, the Taj Mahal, and those who haven't. The same could be said about investors. There are two kinds of investors: those who know about the investment opportunities in India and those who don't. India may look like a small dot to someone in the U.S., but upon closer inspection, you will find the same things you would expect from any promising market.
Share or Stock or Equity. These are three terms which can be used interchangeably. So in an actual sense, these three words mean the same. So if you own a share of a particular company then you have a claim on the ownership of the company.
So, in a nutshell, your claim on the ownership of the company is directly proportional to the amount of share you own or hold in your portfolio. If you hold more than 50% of the shares of a company then you become the majority shareholder and practically the owner of the company. But can you own 50% of the share, that is a debate for another day!