Cyclopedia of Congressional Budget Law
The term sequester is simply the verb form for “sequestration”. If required under the terms of Balanced Budget and Emergency Deficit Control Act of 1985 (BBEDCA), as amended by the Statutory Pay-As-You-Go Act of 2010 (Pub. L. 111-139) and the Budget Control Act of 2011 (Pub. L. 112-25), the President will issue a sequester order which requires that direct spending budgetary resources for a fiscal year, in each non-exempt budget account, be reduced by the amount calculated by the Office of Management and Budget.
GAO Glossary of Terms and Definition (September 2005)
See under Sequestration.
Congressional Budget Process: An Explanation (Senate Budget Committee)
Definitions of Sequester and Sequestrable Resource
Sequester: Pursuant to [the Balanced Budget and Emergency Deficit Control Act of 1985], a presidential spending reduction order that occurs by reducing spending by uniform percentages.
Sequestrable Resource: Pursuant to [the Balanced Budget and Emergency Deficit Control Act of 1985] federal funding authority (budgetary resources) subject to reductions under a presidential sequester order for achieving required outlay reductions (in non-exempt programs).
[The Congressional Budget Process: An Explanation, Appendix J (Glossary), Committee on the Budget of the U.S. Senate, S. Prt. 105-67 (Revised December 1998).]