1. An examination and verification of a company's financial and accounting records and supporting documents by a professional, such as a Certified Public Accountant. 2. An audit is an IRS examination of an individual or corporation's tax return, to verify its accuracy. There are three types of audits: correspondence audits (the IRS mails a request for additional information), office audits (an interview is conducted at a local IRS office), and field audits (an interview is conducted at a taxpayer's place of business, for a corporate tax return). Since there is always the chance of an audit, experts recommend keeping good records to support all the information in a return. The reason detailed and accurate bookkeeping is so important is that the burden of proof is on the filer, not the IRS.