A CEO (which stands for Chief Executive Officer) is the person who leads an entire company and makes the biggest decisions about how it runs. Think of a CEO as similar to a school principal, but for a business: they're ultimately responsible for whether the company succeeds or fails.

The CEO decides the company's direction, like whether to create new products, expand to new cities, or hire more workers. They work with other leaders in the company, but when there's a tough choice to make, the CEO has the final say. For example, if a toy company's CEO believes kids want more outdoor toys instead of video games, she might steer the whole company in that direction.

Large companies usually have a CEO who reports to a board of directors (a group of people who represent the company's owners). Small family businesses might have a CEO too, though an owner often fills that role. Famous CEOs you might have heard of include people who started their own companies and grew them from small startups into huge businesses.

Being a CEO requires understanding many different parts of a business: finance, operations, marketing, and managing people. It's one of the most challenging and demanding jobs in any company, but also one where a talented leader can make an enormous difference in people's lives.