What does "bitter orange tree" mean?

any of various common orange trees yielding sour or bitter fruit; used as grafting stock

Bitter orange tree

Common synonyms include: bigarade, bitter orange, citrus aurantium, marmalade orange, seville orange, sour orange.

Rare ·Advanced level

Noun

1
any of various common orange trees yielding sour or bitter fruit; used as grafting stock wordnet