Nouns

(n)chaira seat for one person, with a support for the back“he put his coat over the back of the chair and sat down”
(n)professorship, chairthe position of professor“he was awarded an endowed chair in economics”
(n)president, chair, chairpersonthe officer who presides at the meetings of an organization“address your remarks to the chairperson”
(n)electric chair, chair, death chair, hot seatan instrument of execution by electrocution; resembles an ordinary seat for one person“the murderer was sentenced to die in the chair”
(n)chaira particular seat in an orchestra“he is second chair violin”

Verbs

(v)chair, chairmanact or preside as chair, as of an academic department in a university“She chaired the department for many years”
(v)moderate, chair, leadpreside over“John moderated the discussion”