module is the name of a package (namespace) that is kept in a file derived from its name. (a package/namespace called Some::Thing kept in a file called Some/Thing.pm is called a module. Unfortunately when we say module we often refer to a whole distribution.
Company officer positions are senior executive-level in nature in most companies and include chief financial officers and, sometimes, chief accounting officers. CFOs and CAOs are also frequently referred to as vice presidents. So, a CFO might be called a vice president of finance and a CAO a vice president of accounting.
A 'company president' is commonly referred to as 'chief operating officer', and is accountable to the 'ceo'. The ceo may be the highest ranking executive, but he/she is still accountable to the board of directors. http://en.wikipedia.org/wiki/Company_president. http://en.wikipedia.org/wiki/Chief_Executive_Officer. And beergirllaura's answer is a good explanation of why the chairman of the board of directors may be the most powerful person in the company, regardless of titles. http://en.wikipedia.org/wiki/Board_of_directors.