Arrangement in health insurance to discourage multiple payment for the same claim under two or more policies. When two or more group health insurance plans cover the insured and dependents, one plan becomes the primary plan and the other plan (s) the secondary plan (s). For example, two working spouses have health insurance at their respective places of employment. If one spouse becomes ill, his/her policy at work would become the primary plan. Medical expenses not covered under the primary plan would be covered under the secondary plan of the other spouse.