This is primarily a term used in the Appropriations process, since it refers
to the pot of money that is made available to the Appropriations Committee
for discretionary spending. The annual budget resolution establishes this
allocation, and the Appropriations Committee then divides up the allocation
into 13 suballocations corresponding to the 13 annual Appropriations bills.
The process is akin to first determining the size of the overall discretionary
spending pie and then dividing that pie up into 13 pieces. There are rules
in the House and the Senate that prohibit considerations of spending bills
that exceed these allocations and suballocations.