El nombre científico puede llevarte a la imagen y así despejar dudas.
pomelo = Citrus maxima
grapefruit = Citrus x paradisi

Me inclino a pensar a que tu fruta es el grapefruit.

For clarity:
https://en.wikipedia.org/wiki/Pomelo
The pomelo, pummelo, or in scientific terms Citrus maxima or Citrus grandis, is the largest citrus fruit from the family Rutaceae and the principal ancestor of the grapefruit.[1] It is a natural, i.e., non-hybrid, citrus fruit, native to Southeast Asia and Malaysia.[1] Similar in taste to a large grapefruit, the pomelo is commonly consumed and used for festive occasions throughout Southeast Asia.

Whereas:
https://en.wikipedia.org/wiki/Grapefruit
The grapefruit (Citrus × paradisi) is a subtropical citrus tree known for its relatively large sour to semi-sweet, somewhat bitter fruit.[1] Grapefruit is a citrus hybrid originating in Barbados as an accidental cross between the sweet orange (C. sinensis) and pomelo (or shaddock) (C. maxima), both of which were introduced from Asia in the seventeenth century.[2] When found, it was nicknamed the "forbidden fruit".[1] Frequently, it is misidentified as the very similar parent species, pomelo.[3]