To think about the meaning of CEO, is to refer to the Chief Executive Officer, or Executive Director. It is the highest position of responsibility within the administration of a organization. In most cases, it refers to large companies that are even usually listed on the stock market. But it's not always like this.
It can also exist in other types of organizations, such as public companies, large associations or non-profit organizations. The usual thing is that it acts together with a board of directors and its function is to maximize the objectives of the company and its shareholders, if applicable.
Although it is widely spread internationally, the acronym CEO can also be considered equivalent to others such as MD, Managing Director, or CE, Executive Director. Sometimes a similar figure is called President. There are also specific names in certain countries, such as the Representative Director, RD, which is the name for the CEO in Japan.
A CEO usually has as functions or responsibilities the administration of the company's resources, making important decisions or the general administration of operations; and, above all, is in charge of drawing up the company's strategy. However, the role varies between companies.
The CEO often sits on the Board of Directors, even serving as Chairman. In another case, it will be a communication bridge between the day to day of the company and the aforementioned Board of Directors.
The figure of the CEO also appears as General Manager in SMEs. In this case, it is frequent that it has a very active role, and that its functions notably exceed those mentioned above.
In this sense, decisions are included, perhaps of a lower level, which in a large company would be aimed at human resources such as, hiring of personnel, or would correspond to the commercial or marketing department, such as purchasing or sales decisions, etc ...