auditor
US /ˈɑː.də.t̬ɚ/
UK /ˈɑː.də.t̬ɚ/

1.
a person who conducts an official financial inspection of a company or individual's accounts
:
•
The company hired an independent auditor to review their financial statements.
•
As an auditor, her job is to ensure financial accuracy and compliance.
2.
a person who listens, especially to a lecture or broadcast
:
•
The professor addressed the auditors in the lecture hall.
•
She attended the class as an auditor, not for credit.