Definition:
An instrument that signifies an ownership position (called equity) in a corporation, and represents a claim on its proportional share in the corporation's assets and profits. Ownership in the company is determined by the number of shares a person owns divided by the total number of shares outstanding.
Definition: A stock (also known as an equity or a share) is a portion of the ownership of a corporation. A share in a corporation gives the owner of the stock a stake in the company and its profits. If a corporation has issued 100 stocks in total, then each stock represents a 1% ownership in the company.
In finance a share is a unit of account for various financial instruments including stocks, mutual funds, limited partnerships, and REIT's. In British English, the usage of the word share alone to refer solely to stocks is so common that it almost replaces the word stock itself.