For the most part, any stock can be an investment stock. The exception to this could be considered penny stocks or hot stock as they are day traded and involve a higher risk for a lower return. An investment stock is buying a shares in a company, also known as investing in that company. Investment stocks are bought and sold in a stock exchange on the stock market.
The idea behind investing in stock is to make money without really working. This is not as lazy as it sounds. It takes a fair amount of research to invest wisely. Investment stocks are not just bought at random or based on hunches. Whether you are going to do your investing yourself or through a broker, it takes research. You want to invest soundly in a company which means using stock analysis to determine what shares to buy. You would also use stock analysis to choose when to hold, buy, or sell. If you choose to invest using a broker you will have to research brokers to find one that will fit your risk tolerance and trading style.
Stocks in general will have a greater return than other forms of investments, including bonds and CDs and even real estate. Stocks, if invested and managed wisely, can yield a return of approximately 10%, whereas other types of cash and capital investments will only generally return 5-7%.