What exactly is an executive chair, Tim Cook’s new position?

On April 20, Apple announced that Tim Cook will step down as CEO on August 31 and, effective September 1, become Executive Chair of the Board of Directors. John Ternus, currently Senior Vice President of Hardware Engineering, will succeed Cook as CEO and join the board. Arthur Levinson, who has been Apple’s chairman since November 2011, will become Lead Independent Director. &#xA; Cook’s departure…