302(a): The macro spending amount in the Budget Resolution for discretionary spending. 302(a) refers to the authorization language in the Congressional Budget Act of 1974 providing authority in the Budget Resolution. After the 302(a) is approved in the Budget Resolution the Appropriations chair can then set about allocating 302(b).
302(b): The specific spending amounts allocated to the 12 subcommittees as set by the chairman and ratified by the Full Committee. 302(b) refers to the authorization language in the Congressional Budget Act of 1974 providing authority in the Budget Resolution.
Authorizing vs. Appropriations Bills: An Authorization Bill provides the authority for a program or agency to exist and determines its policy. It also recommends spending levels to carry out the defined policy, but these levels are not binding. Authorizations may be annual, multi-year, or permanent. Expiring programs require re-authorization. House and Senate rules require that authorizations be in place before final funding decisions are made. An Appropriations Bills provides the legal authority needed to spend or obligate U.S. Treasury funds. There are 12 annual appropriations bills which together fund the entire federal government. These 12 bills must all be enacted prior to the start of a new fiscal year, designated as October 1. Failure to meet this deadline causes the need for temporary short-term funding or results in a shut-down.
Continuing Resolution: Also known as a "CR," continues funding for a program if the fiscal year ends without a new appropriation in place. A "CR" provides temporary funding at current levels or less and is generally intended to extend the amount of time available to complete the following fiscal year's appropriations bills.
Mandatory vs. Discretionary Spending: Refers to spending set by annual appropriation levels made by decision of Congress. This spending is optional, and in contrast to entitlement programs for which funding is mandatory. Mandatory spending refers to funds not controlled by annual decision of Congress. These funds are automatically obligated by virtue of previously-enacted laws.
Mark-Up: Refers to the meeting of a Committee held to review the text of a bill before reporting it out. Committee members offer and vote on proposed changes to the bill's language, known as amendments. Most mark-ups end with a vote to send the new version of the bill to the floor for final approval
Omnibus Bill: Packages together several measures into one or combines diverse subjects into a single bill. Examples are reconciliation bills, combined appropriations bills, and private relief and claims bills.
Supplemental Appropriations: Provides funds in addition to the 12 regular appropriations level. Supplementals often arise when an emergency, e.g. disaster relief, requires immediate funding.