What is a "stake?" A stake is often used to describe the amount of stock an investor owns, and this is certainly a correct way to use the word. If you own stock in a given company, your stake represents the percentage of its stock that you own.

stake². / (stejk) / noun. the money or valuables that a player must hazard in order to buy into a gambling game or make a bet. an interest, often financial, held in something: a stake in the company's future.