Seville orange

US /ˌsev.ɪl ˈɔːr.ɪndʒ/
UK /ˌsev.ɪl ˈɔːr.ɪndʒ/
"Seville orange" picture
1.

a bitter orange, Citrus aurantium, native to southeastern Asia, cultivated in warm regions, and used for marmalade and as a rootstock.

:
She made a delicious marmalade using Seville oranges.
The unique bitterness of Seville oranges makes them ideal for marmalade.