perfect fieldperfect graphperfect groupperfect n th powerperfect numberperfect powerperfect setperfect squareperfectionperfectlyperforatingperforatorperformperformanceperformance budgetingperformance ratingperformance ratiopericenterpericycloidperigeeperigonperihelionperimeterperimeter of a polygonperinelionperiodperiod budgetperiod curveperiod in arithmeticperiod in astronomyperiod intervalperiod of a functionperiod of a repeating decimalperiod of an elementperiod of oscillaionperiod parallelogramperiodicperiodic behaviourperiodic constantperiodic continued fractionperiodic decimalperiodic decimal fractionperiodic decimalsperiodic functionperiodic function of a complex variableperiodic function of a real variableperiodic inspectionperiodic inventory systemperiodic motionperiodic number
