Merriam-Webster Collegiate Dictionary - pomelo

 noun  (plural -los)  Etymology: probably alteration of earlier pompelmous, from Dutch pompelmoes  Date: 1858  1. grapefruit  2. (or pummelo)  a. a very large thick-rinded usually pear-shaped citrus fruit differing from the closely related grapefruit especially in its loose rind and often coarse dry pulp  b. a large widely cultivated tropical tree (Citrus maxima syn. C. grandis) of southeast Asia that bears ~s