What is the difference between 1. Chief Executive Officer, 2. Chief Operation Officer, 3. General Secretary, 4. Executive Secretary, 5. DG/MD/GM?

CEO (Chief Executive Officer): is a top-ranking corporate position, responsible for overseeing operations. Often the company's president, the CEO reports to the chairman of the board and board members.

COO (Chief Operation Officer): is responsible for the daily operation of the company, and routinely reports to the highest ranking executive. The COO may also carry the title of President which makes that person the second at the firm and enjoying an equal privilege with Chief Services Officer, especially if the highest ranking executive is the Chairman and CEO

General Secretary: is a key one on the Executive Committee.  It requires energy and sustained commitment.  It is demanding in its necessary attention to detail.  It is best suited to a person who is well organized, has developed administrative skills and has appropriate, but by no means elaborate, secretarial assistance

Executive Secretary: Responsible for supporting high-level executives and management or entire departments. Provides administrative support and performs numerous duties, including scheduling, writing correspondence, emailing, handling visitors, routing callers, and answering questions and requests.

The Managing Director (MD): is the most senior role in any company. With ultimate responsibility for the company’s performance the Managing Director will report in to the Chairman and shareholders whilst leading a Board of Directors. Primarily the Managing Director will be responsible for implementing company policy and any changes to it. The Managing Director will be responsible for representing the company in public at events or with the press. They will be responsible for leading, coaching and mentoring other board members and supporting their professional development. 

Chief Executive Officer, General Secretary, Executive Secretary, Managing Director, Directory General and General Manager all mean much the same thing.   The difference is mostly in the historical, national and cultural context, and the type of organisation (whether commercial, public sector, trade union, etc.)

Chief Operating Officer is a role which is not well defined, but tends to suggest responsibility for the day-today operation of the company.   The COO usually reports to the CEO.