seville orange

Seville orange
    n 1: any of various common orange trees yielding sour or bitter
         fruit; used as grafting stock [syn: {sour orange}, {Seville
         orange}, {bitter orange}, {bitter orange tree}, {bigarade},
         {marmalade orange}, {Citrus aurantium}]
    2: highly acidic orange used especially in marmalade [syn:
       {bitter orange}, {Seville orange}, {sour orange}]