1. A formal examination, correction, and official endorsing of financial accounts; especially, those of a business, undertaken annually by an accountant.
2. A systematic check or assessment; especially, of the efficiency or effectiveness of an organization or a process, typically carried out by an independent assessor.
3. In computer programming: a process used to detect accidental input or processing errors as well as fraud, often using test data and special-purpose software.
4. Another aspect of computer programming in which a set of procedures are established to ensure the quality and integrity of a data base and to carry out such a process or procedure.
5. Etymology: from Latin auditus, "a hearing"; past participle of audire, "to hear".

It now stands for the official examination of business accounts, which were originally oral or spoken. The verb is from about 1557.

In computer programming, a known quantity or sum that is used to verify intermediate or final results of data processing, usually in an accounting or other financial application.