It's good to refer to this fruit as pummelo due to common name confusion with pomelo, which means grapefruit in many countries.
From Morton:
This (pummelo) the largest citrus fruit, is known in the western world mainly as the principal ancestor of the grapefruit. As a luscious food, it is famous in its own right in its homeland, the Far East.
Botanically it (pummelo) is identified as Citrus maxima Merr., (C. grandis Osbeck; C. decumana L.). The common name is derived from the Dutch pompelmoes, which is rendered pompelmus or pampelmus in German, pamplemousse in French. An alternate vernacular name, shaddock, now little used, was acquired on its entry into the Western Hemisphere as related below. The current Malayan names are limau abong, limau betawi, limau bali, limau besar, limau bol, limau jambua, Bali lemon, and pomelo.