Definitions:
a separate seat for one person, typically with a back and four legs.

the person in charge of a meeting or of an organization (used as a neutral alternative to chairman or chairwoman)

a professorship

a metal socket holding a rail in place on a railway sleeper.

act as chairperson of or preside over (an organization, meeting, or public event)

carry (someone) aloft in a chair or in a sitting position to celebrate a victory