Citrus maxima

The pomelo ( POM-il-oh, PUM-; or pummelo, Citrus maxima), also known as a shaddock, is the largest citrus fruit. It is an ancestor of several cultivated citrus species, including the bitter orange and the grapefruit. It is a natural, non-hybrid citrus fruit, native to Southeast Asia. Similar in taste to a sweet grapefruit, the pomelo is commonly eaten and used for festive occasions throughout Southeast and East Asia. As with the grapefruit, phytochemicals in the pomelo have the potential for drug interactions....read more on Wikipedia.