Any evaluation of the budgetary consequences of a policy, enacted law, or legislation might be termed a budget estimate; the term is normally associated with analyses prepared, and required by law, for legislation to be considered by Congress by the Congressional Budget Office (CBO). These estimates are prepared under the authority and terms of sections 202, 308, 312, and 402 of the Congressional Budget Act of 1974, though they are referred to by other provisions of law.
Importantly, under the terms of the Statutory Pay-As-You-Go Act of 1974, if no CBO estimate has been included with the text of “paygo legislation”, then estimates prepared by the Office of Management and Budget are used to determine whether sequestration is necessary for a fiscal year.
GAO Glossary of Terms and Definition (September 2005)
Estimates of budget authority, outlays, receipts, budget amendments, supplemental requests from the President, or other budget measures that cover the current, budget, and future years, as reflected in the President’s budget and budget updates. (See also Budget Update.)
Budget Enforcement Act of 1997
Budget of the U.S. Government