1.chairman的意思是“坐在椅子上主持会议的人”,即“主席”,也可指委员会的“委员长”,董事会的“董事长”。其复数形式为chairmen。
2.chairman主要指男性,也可指女性。女主席还可说chairwoman。
3.chairman表示独占的职位时,通常不加冠词,如指具体的人则须加冠词。

The chairman called the meeting to order.主席宣布开会。
The chairman presided over the meeting.主席主持会议。
Many people spoke at the meeting, and finally the chairman summed up the discussion.许多人在会上发了言,最后主席总结了这次讨论。
After everyone was seated, the chairman proceeded to announce his plan.每个人都坐好后,主席才开始宣布他的计划。
The chairman rapped on the table for order.主席敲桌子要求安静。
The chairman gave an opening address.主席致开幕词。
As the chairman is ill,I'm asking Mr. Sharp to act for him.由于主席患病,我请夏普先生代理主席一职。
He had the honour of being presented to the chairman in the office.他有幸在办公室被主席召见。
He proposed that young man to be the chairman.他提名那个年轻人做主席。
Kindly address yourself to the chairman, not directly to other representatives at this meeting.请你向主席讲,不必直接向与会代表讲。
She likes being called Madam Chairman.她喜欢被人称为主席阁下。

chairman, chair, chairperson
参见chair条。