42 C.F.R. § 417.401
As used in this subpart and subparts K through R of this part, unless the context indicates otherwise-
Adjusted average per capita cost (AAPCC) means an actuarial estimate made by CMS in advance of an HMO's or CMP's contract period that represents what the average per capita cost to the Medicare program would be for each class of the HMO's or CMP's Medicare enrollees if they had received covered services other than through the HMO or CMP in the same geographic area or in a similar area.
Adjusted community rate (ACR) is the equivalent of the premium that a risk HMO or CMP would charge Medicare enrollees independently of Medicare payments if the HMO or CMP used the same rates it charges non-Medicare enrollees for a benefit package limited to covered Medicare services.
Arrangement means a written agreement between an HMO or CMP and another entity, under which-
Benefit stabilization fund means a fund established by CMS, at the request of a risk HMO or CMP, to withhold a portion of the per capita payments available to the HMO or CMP and pay that portion in a subsequent contract period for the purpose of stabilizing fluctuations in the availability of the additional benefits the HMO or CMP provides to its Medicare enrollees.
Cost contract means a Medicare contract under which CMS pays the HMO or CMP on a reasonable cost basis.
Cost HMO or CMP means an HMO or CMP that has in effect a cost contract with CMS under section 1876 of the Act and subpart L of this part.
Demonstration project means a demonstration project under section 402 of the Social Security Amendments of 1967 (42 U.S.C. 1395b-1 ) or section 222(a) of the Social Security Amendments of 1972 (42 U.S.C. 1395b-1 (note)), relating to the provision of services for which payment is made under Medicare on a prospectively determined basis.
Emergency services means covered inpatient or outpatient services that are furnished by an appropriate source other than the HMO or CMP and that meet the following conditions:
Once initiated, the services continue to be considered emergency services as long as transfer of the enrollee to the HMO's or CMP's source of health care or authorized alternative is precluded because of risk to the enrollee's health or because transfer would be unreasonable, given the distance and the nature of the medical condition.
Geographic area means the area found by CMS to be the area within which the HMO or CMP furnishes, or arranges for furnishing, the full range of services that it offers to its Medicare enrollees.
Medicare enrollee means a Medicare beneficiary who has been identified on CMS records as an enrollee of an HMO or CMP that has a contract with CMS under section 1876 of the Act and subpart L of this part.
New Medicare enrollee means a Medicare beneficiary who-
Risk contract means a Medicare contract under which CMS pays the HMO or CMP on a risk basis for Medicare covered services.
Risk HMO or CMP means an HMO or CMP that has in effect a risk contract with CMS under section 1876 of the Act and subpart L of this part.
Urgently needed services means covered services that are needed by an enrollee who is temporarily absent from the HMO's or CMP's geographic area and that-
42 C.F.R. §417.401