名詞 grapefruit:

1. citrus tree bearing large round edible fruit having a thick yellow rind and juicy somewhat acid pulp
   同義詞：Citrus paradisi
2. large yellow fruit with somewhat acid juicy pulp; usual serving consists of a half

1. Any of a group of water-soluble colloidal carbohydrates of high molecular weight found in ripe fruits, such as apples, plums, and grapefruit, and used to jell various foods, drugs, and cosmetics.
   果膠任一種用于凝結各種食物、藥品和化裝品的高分子量且溶于水的膠質碳水化合物，存在于如蘋果、杏和葡萄等成熟的水果中
2. He split the grapefruit in two.
   他把柚子分成兩半。

grape.fruit

n.（名詞）
A tropical or semitropical evergreen(Citrus paradisi) cultivated for its edible fruit.
葡萄柚：一種熱帶或亞熱帶常綠（柑桔屬 葡萄柚） ，因其果實可食而被栽培
The large, round fruit of this tree, having a yellow rind and juicy, somewhat acid pulp.
葡萄柚果：這種樹的大的圓形果實，生黃皮和多汁的，略酸的漿肉

來源：
[Probably so called because the fruit grows in clusters]
[可能因其果實簇生而得名]