audit
au·dit
I
 /ˈɑːdət/  noun  ,  pl   -dits
  1 : a complete and careful examination of the financial records of a business or person
   [  count  ] The audit showed that the company had mislead investors.
    The Internal Revenue Service selected us for an audit.
   [  noncount  ] You will need all your records if you are selected for audit by the IRS.
  2 [  count  ] : a careful check or review of something
   Our local power company will perform an energy audit [=survey, inspection] of our house.
   Investigators called for an audit [=review, analysis] of flight safety standards.
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II
  verb  , -dits, -dit·ed, -dit·ing [  + obj  ]
  1 : to check the financial records of (a business or person) : to perform an audit on (a business or person)
   They audit the company books every year.
   The Internal Revenue Service audited him twice in 10 years.
  2 US : to attend a course at a college or university without having to do any of the course work and without receiving credit
   I audited an English literature class last semester.