Definition: A "stock split" is a financial event that occurs when a company increases the number of its shares. This means that each existing share is divided into more shares. However, the total value of the company and the total money that shareholders have remains the same.
In more advanced contexts, you might discuss the reasons why a company would do a stock split, such as making the stock price more attractive to investors or to increase liquidity.
A stock split is a way for companies to adjust their share numbers without changing their overall value.