Of a company such as GM or Sony or whatnot.
This is how it looks to me:
President is the the highest-ranking corporate officer. Chairman of the Board [of Directors] is just what the name implies. CEO is the one who makes the ultimate decisions. Sometimes the President is the CEO; sometimes the Chairman is; sometimes the same person is Chairman, President, and CEO.
Anyone have a more precise answer?
This question was answered moderately well a few months ago, but it seems like it would be hard to search for, so I’ll go ahead and give it a try.
Basically, you can only have one CEO (well, there are instances of 2, but they are refered to as Co-CEOs). You can have as many presidents as you like. So, Intel for instance has a CEO (Andy Grove), and a bunch of presidents; I’m sort of guessing at the titles, but they mighty have a president, CA manufacturing and President, European Sales, etc.
In a small company, it is customary for the President to be the CEO.
The Chairman of the Board is elected by the board of directors. The board, in publically held companies, are elected by the stockholders. The board hires and fires CEOs, CEOs hire and fire presidents.
The chairman of the board is not supposed to be involved in day to day running of the company.
Make any sense?
A President is the head of a nation and has broad, far-reaching, unilateral powers. They are elected by all the people of the country, ostensibly to do the greatest good for all. They serve short terms, and if they perform their job poorly, they don’t get reelected, and perhaps even get impeached.
A CEO is the head of a business and has broad, far-reaching, unilateral powers, possibly even globally. They are usually installed by a small cadre of the upper echelon of the given company, for long spans of time, usually far from the reach of public disapproval, and they have only one task: to do the greatest good for the company. To hell with everyone/everything else.
(c’mon, it’s GD, someone had to spur the debate) 
Damn skippy!
I’m just trying to recall fuzzy information… if I’m inaccurate, well, sue me.
First off, there are several different sides of a company… there’s the investors, who put in money to make the money stronger on the chance that their contribution will increase production. This side is the most powerful aspect of a company, and the Chairman of the Board is at the top of this particular pyramid.
Another side is the aspect that controls the “game plan” of the company. They make the big decision, receive the information from different departments, and decide the ultimate fate of the company. The CEO is the top of this pyramid.
Then there’s the grunt-work, the different departments that have different goals. For example, Sony’s Playstation department and Sony’s Vaio department (I don’t know if those are the real names) would have very different purposes and would want to hire different people. I imagine that President’s are in charge of each individual department.
Again, this information was gathered piece-by-piece over the course of several years, a while back, so it may be spotty.
A corporate “president” has a role defined by state law.
Every corporation is required by the laws of the State to have at least 3 officers: a president, a secretary, and a treasurer. All 3 of these officers are considered employees of the corporation, and in most states one individual is allowed to take on more than one of these roles. It is possible for you, and you alone, to be the corporation’s entire set of stockholders, its entire board of directors, its president, its secretary, and its treasurer.
The president has several required duties involving the day-to-day operation of the corporation’s business. These duties often interfere with the need for the corporation to make long-term strategic decisions. Thus, most modern corporations (larger than the “one-man band” corporations I mentioned at the end of the previous paragraph) hire another individual expressly for the purpose of making these strategic decisions. This person is called the “Chief Executive Officer,” or CEO. There is nothing in the State’s corporate laws requiring a CEO or specifying the CEO’s duties. This is the main difference between a President and a CEO.
Here’s a link to the earlier thread.