What does "Schedule P" reserve mean?

"Schedule P" reserve meaning in Insurance Dictionary

an obligation loss book regarding the business compiled by a property-casualty (P&C) insurer that needs to be shown on Plan P associated with the convention blanks required by the National Association of Insurance Commissioners (NAIC). The objective of the reserve is always to provide for an assessment for the monetary strength of this insurer during a period of time as losings develop relative to earned premium.