Definitions of chair:

• noun:   a seat for one person, with a support for the back

  Example: "He put his coat over the back of the chair and sat down"

• noun:   the position of professor

  Example: "He was awarded an endowed chair in economics"

• noun:   an instrument of execution by electrocution; resembles a chair

  Example: "The murderer was sentenced to die in the chair"

• noun:   the officer who presides at the meetings of an organization

  Example: "Address your remarks to the chairperson"

• verb:   act or preside as chair, as of an academic department in a university

  Example: "She chaired the department for many years"

• verb:   preside over