There are general rules and concepts that govern the field of accounting. These general rules–referred to as basic accounting principles and guidelines–form the groundwork on which more detailed, complicated, and legalistic accounting rules are based. For example, the Financial Accounting Standards Board (FASB) uses the basic accounting principles and guidelines as a basis for their own detailed and comprehensive set of accounting rules and standards.
The phrase “generally accepted accounting principles” (or “GAAP”) consists of three important sets of rules: (1) the basic accounting principles and guidelines, (2) the detailed rules and standards issued by FASB and its predecessor the Accounting Principles Board (APB), and (3) the generally accepted industry practices.