What is Accounting?

Legal Definition
Accounting or accountancy is the measurement, processing and communication of financial information about economic entities such as businesses and corporations. The modern field was established by the Italian mathematician Luca Pacioli in 1494. Accounting, which has been called the "language of business", measures the results of an organization's economic activities and conveys this information to a variety of users, including investors, creditors, management, and regulators. Practitioners of accounting are known as accountants. The terms 'accounting' and 'financial reporting' are often used as synonyms.

Accounting can be divided into several fields including financial accounting, management accounting, external auditing, and tax accounting. Accounting information systems are designed to support accounting functions and related activities. Financial accounting focuses on the reporting of an organization's financial information, including the preparation of financial statements, to external users of the information, such as investors, regulators and suppliers; and management accounting focuses on the measurement, analysis and reporting of information for internal use by management. The recording of financial transactions, so that summaries of the financials may be presented in financial reports, is known as bookkeeping, of which double-entry bookkeeping is the most common system.

Accounting is facilitated by accounting organizations such as standard-setters, accounting firms and professional bodies. Financial statements are usually audited by accounting firms, and are prepared in accordance with generally accepted accounting principles (GAAP). GAAP is set by various standard-setting organizations such as the Financial Accounting Standards Board (FASB) in the United States and the Financial Reporting Council in the United Kingdom. As of 2012, "all major economies" have plans to converge towards or adopt the International Financial Reporting Standards (IFRS).
-- Wikipedia
Legal Definition
1) The procedure of recording, analyzing, summarizing and classifying the financial transactions and information of a person or business which aids in accurate administration of resources.

2) A plaintiff's legal action to recover money owed to the plaintiff by the defendant. Also known as accounting for profits.
Illustrative case law
See, e.g. Free Enterprise Fund v. Public Co. Accounting Oversight Bd., 130 S.Ct. 3138 (2010).
See also
Legal Definition
The making up and rendition of an account, either voluntarily or by order of a court. Buxton v. Edwards, 134 Mass. 567, 578. May include payment of the amount due. Pyatt v. Pyatt, 46 N. J. Eq. 285, 18 Atl. 1048.
-- Black's Law Dictionary
Legal Definition
The rendition of an account.
-- Ballentine's Law Dictionary