1. Any of various common orange trees yielding sour or bitter fruit; used as grafting stock
   "They made traditional marmalade from sour oranges";
   - Seville orange, bitter orange, bitter orange tree, bigarade, marmalade orange, Citrus aurantium
    
2. Highly acidic orange used especially in marmalade
   "She made marmalade from sour oranges";
   - bitter orange, Seville orange

Derived forms: sour oranges

Type of: orange, orange tree

Part of: genus Citrus

Encyclopedia: Sour orange