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.
CEO, CFO and CIO are titles for top executives at a corporation. - The CEO is the Chief Executive Officer, the big boss. However, in corporations they report to the board of directors who have ultimate control and responsibility, including hiring and firing the CEO. - A CFO is Chief Financial Officer.