A continuing resolution, or a “CR” for short, is legislation that allows the federal government to keep operating and spending money when regular appropriation acts have expired and new authority has not yet been enacted.
A CR is enacted as a joint resolution, which must pass both the House and Senate and be signed by the President. It can run for an entire fiscal year, just a few weeks, or even days. Usually the CR specifies the rate at which spending can occur, in most cases extending operations at current levels. (See: GAO Budget Glossary, Senate glossary)
The Government Accountability Organization (GAO) in a 2013 report:
Because CRs only provide funding until agreement is reached on final appropriations, they create uncertainty for agencies about both when they will receive their final appropriation and what level of funding ultimately will be available. Effects of CRs on federal agencies differ based in part on the duration and number of CRs and may vary by agency and program. CRs include provisions that prohibit agencies from beginning new activities and projects and direct agencies to take only the most limited funding actions. Congress can provide flexibility for certain programs and initiatives through the use of legislative anomalies, which provide funding and authorities different from the standard CR provisions.
For more information, see: “Continuing Resolutions: Overview of Components and Recent Practices,” from the nonpartisan Congressional Research Service.