This excerpt taken from the CVS DEF 14A filed Mar 25, 2005.
A quorum of stockholders is necessary to hold a valid meeting. The presence in person or by proxy at the meeting of holders of shares representing a majority of the votes of the common stock and the ESOP preference stock entitled to vote constitutes a quorum. Abstentions and broker non-votes are counted as present for establishing a quorum. A broker non-vote occurs on an item when a broker is not permitted to vote on that item absent instruction from the beneficial owner of the shares and no instruction is given.