🌳 A grafting tree 🍊 A tart fruit

sour orange

1 5.0

A tree that makes bitter oranges used as root for other orange trees and for marmalade

noun
/ˈsaʊər ˈɔrɪndʒ/

: naranja agria

They often use sour oranges when making traditional marmalade for its unique bitter taste.

Examples

Quick-decline strains can rapidly kill trees on sour orange rootstock but do not affect trees on other types of rootstocks.

Academic text (1994)
All sweet orange, grapefruit, and mandarin trees grown on sour orange rootstock are susceptible to quick decline.

Academic text (1994)
In many Caribbean dishes, sour oranges are a key ingredient, adding a tart flavor to marinades.
For the recipe, you will need the juice of three sour oranges to enhance the dish's acidity.

Synonyms

Seville orange

vssour orange

1 6.5

A bitter sour orange used to make marmalade and to grow other citrus trees

is the general tree name used across cooking and grafting

wild orange

vssour orange

1 8.5

A small tree with fragrant flowers and bitter, inedible fruit

is the cultivated form valued for cooking and as grafting stock

bitter orange

vssour orange

5.9

A type of orange tree that produces small sour fruit and is used for grafting and marmalade

is the common cooking and rootstock term rather than the scientific name

Citrus aurantium

vssour orange

Specialized

7.7

An orange tree with bitter fruit used for marmalade and flavoring

is the everyday name for that same fruit and grafting use

bitter orange tree

vssour orange

6.3

A tree that produces sour oranges used for marmalade and grafting

is the broader cooking and rootstock term for such trees

marmalade orange

vssour orange

6.9

A small orange tree that makes sour fruit used for marmalade and to start new orange trees

is the general term for trees with bitter cooking fruit

bigarade

vssour orange

Specialized

9.9

A type of orange tree that makes bitter fruit and is used to grow other orange trees

is the broader label for similar sour fruit trees used in cooking

Surface Forms

sour orange singular

sour oranges plural

Morphology

sour + orange

The adjective 'sour' (acidic/tart) combined with the noun 'orange' yields the straightforward compositional meaning 'an orange that tastes sour,' which matches the provided definition. This adjective+noun pattern is cross-linguistically common and follows regular English composition, so a B1 learner who knows both words will readily infer the MWE's meaning.

Etymology

Sour orange names a tree and its fruit with a sharp, bitter taste. Imagine a sour orange that makes your mouth pucker; because the tree is strong, gardeners often attach sweeter orange branches to its roots, so the name refers to both the tart fruit and the tree used for that purpose.