Simply stated, a stock is a share in the ownership of a company. Stock (aka shares or equity) is a shareholder’s claim on the corporation’s assets and earnings. The more stock acquired, the higher the ownership stake in the company.
Every shareholder does not have the right to tell the company’s CEO how to run the business. Rather, each share of stock is allowed one vote to elect the board of directors who will oversee the running of the company.
Stock is traditionally represented with a stock certificate, a piece of paper denoting ownership, and once could only be traded in person. Today almost all stocks are kept electronically “in street name" by a representing brokerage firm allowing for quick and easy trading at the click of a mouse or over the phone.