trifoliate orange
noun
: a thorny Chinese tree (Poncirus trifoliata) of the rue family related to the citruses that has trifoliolate leaves and a sour yellow fruit resembling a small orange and that is grown for ornament or hedges or used as a rootstock for citrus fruits
Example Sentences
Recent Examples on the Web It may have been grafted onto a trifoliate orange rootstock. 
Neil Sperry, San Antonio Express-News, 25 June 2021 An extremely easy-to-grow citrus is the trifoliate orange. Howard Garrett, Dallas News, 5 May 2020
Neil Sperry, San Antonio Express-News, 25 June 2021 An extremely easy-to-grow citrus is the trifoliate orange. Howard Garrett, Dallas News, 5 May 2020 Word History
First Known Use
circa 1900, in the meaning defined above