Executive director

An executive director is a member of a board of directors for an organisation, but the meaning of the term varies between countries.
United States.
In the US, an executive director is a chief executive officer (CEO) or managing director of an organization, company, or corporation. The title is widely used in North American not-for-profit organizations, though many United States nonprofits have adopted the title president or CEO.
Confusion can arise because the words "executive" and "director" occur both in this title and in titles of various members of some organizations' boards of directors.
Role.
The role of the executive director is to design, develop and implement strategic plans for the organization in a manner that is both cost and time-efficient. The executive director is also responsible for the day-to-day operation of the organization, which includes managing committees and staff as well as developing business plans in collaboration with the board. In essence, the board grants the executive director the authority to run the organization. The executive director is accountable to the chairman of the board of directors and reports to the board on a regular basis – quarterly, semiannually, or annually. The board may offer suggestions and ideas about how to improve the organization, but the executive director decides whether or not, and how, to implement these ideas.
The executive director is a leadership role for an organization and often fulfills a motivational role in addition to office-based work. Executive directors motivate and mentor members, volunteers, and staff, and may chair meetings. The executive director leads the organization and develops its organizational culture.
United Kingdom (UK).
In the UK, an executive director is a member of a board who is also an employee with a senior role. It is common for boards to have several executive directors, e.g. for different departments.
There is no legal difference between an executive and a non-executive director (NXD or NED), but there are considerable 
differences in the expectations associated with the role.