A stock split is when a company divides its stock into multiple shares, effectively lowering the price of each share without changing the company's market value. It's akin to cutting a cake into smaller slices; you end up with more pieces, but the total amount stays the same. For instance, in a two-for-one split, an investor who owned one share priced at $100 would end up with two shares, each worth $50 but with the same total value.