Pomelos resemble grapefruit, but they are a species in their own right and are an ancestor of the grapefruit, and not a hybrid. They are sometimes called shaddocks after the sea captain who brought them from Polynesia to the West Indies in the mid 17th century. They still grow wild in the region of Malaysia and Indonesia, where they probably originated. There is evidence that the pomelo grew in China as early as 100 BCE and spread westwards in the wake of other, more prized, citrus fruits. Arabs took it to Spain, where it was cultivated on a small scale. The European climate is too cool for it to grow successfully. The tree grows to between twenty and forty feet, producing fuzzy leaves like those of the orange tree and large white flowers. The large, pear-shaped fruit has lemon-yellow skin and pale white or red flesh. It is much larger than grapefruit, with thick yellow dimpled skin, and can measure up to a foot in diameter; although much of its bulk is the thick, loose skin. It was in the West Indies that the fruit was developed into a thinner-skinned and juicier specimen. Whether this was the result of mutation or of hybridization is still in doubt. The flesh is pinkish-yellow and easily separates into segments, but the flavour is sharp and often needs a little sweetening to make it palatable. Despite this, it is usually eaten fresh. It is common for the pomelo to have sixteen to eighteen segments, much more than the grapefruit's twelve. Pomelos sold today are more likely to be a smaller, rounder, and smoother-skinned cross between the original pomelo or shaddock and grapefruit.

The origin of the name can be traced back to the Malay word "pumpulmas", which became the Dutch word "pompelmoes", which then, somehow was transformed into the English "pomelo" (sometimes spelled pummelo). One old English nickname, closer to the Dutch, was pimplenose. Another nickname "Adam's apple" was given in 1187 by a pilgrim to "Palestine", who encountered the fruit with the "marks of Adam's teeth plainly seen" in the rind. This particular variety with these indentations is mentioned by later writers as well. Pomelos range in size from that of a large grapefruit to basketball size and can weigh over twenty pounds, but most are the size of a small canteloupe. The pomelo can be grouped into three types according to area of development: Thai, Chinese, and Indonesian. The Thai group is variable in shape and usually smaller in size than the others, although it is generally regarded as being of a higher quality. The Chinese group contains a large number of fruits, including giant oblate ones with thick rinds but plenty of juice. The Indonesian group is also extremely varied, but does tend to be larger and rounder than the others. Superior pomelos grow in warm tropical regions, particularly in sheltered areas near the sea; but it is also hearty enough to withstand brackish water and poor drainage. Pomelo growers in Southeast Asia are primarily of Chinese ancestry who like swampy land to dredge and then dig canals. These canals act as both drainage systems and transportation routes. The pomelos are cultivated in raised beds and in soil that has already produced such quick crops as sugarcane, bananas, or peanuts.

The pummelo is part of one common Asian family ritual. Following dinner, the family elder carefully opens the fruit at its crown and then pulls away the outer rind. With the pith acting as a casing, the juice sacs of the pulp are easily removed from the segments. The fruit is then passes along the table so that each person can take a segment or two without allowing the juice to escape or soil the hands. Pomelos cannot be eaten with a spoon like grapefrui. They are best peeled with all the pith and thick white membrane removed. To remove the rind requires a knife, but the best way is to make four or five cuts lengthwise in the rind without cutting into the flesh, then pull away these sections and peel from there.

Three pommelo-grapefruit crosses are the Oroblanco, Melogold, and Pomelit. All are super sweet. The pomelit was developed by the Israelis as a new export fruit. The ripe fruit has a green to greenish-yellow skin, with a slight cone-shaped top like a pomelo; but it has the size of a large grapefruit. The green skin does not mean it is unripe. Many of the tropical citrus fruits have green skins. The fibers and skin over the segments are tough like that of a pomelo, but the flesh is sweeter than a grapefruit and juicier than a pomelo. Pomelits are best eaten raw.

Some varieties of pomelo include:

Chandler is the most common, having a deliciously sweet pink flesh and some seeds.

Hirado Buntan was named and introduced into cultivation about 1960, and is one of the most commercial of Japanese fruits. It is yellow, much like a grapefruit in size and shape; but its yellow-pink, bluish coloured flesh is less juicy and firmer. It has numerous segments, as well as seeds, and a tough sinewy wall that gives it an interesting consistency. To obtain the maximum in sweetness, a pomelo should ripen at room temperature for ten to fifteen days until it has a heavy aroma and a deep yellow colour.

Liang Ping Yau is a very large Chinese pomelo and highly prized in Southeast Asia, where it is considered the best citrus for desserts and other culinary purposes. It is shaped almost like a pyramid, with a very thick, pale yellow rind that protects its red, juicy sweet pulp. The pulp is comprised of up to fourteen segments, with many seeds. Its irregular segments create a mosaic pattern when seen in a cross-section. This pleasant flavoured fruit is often eaten with a honey dip in the Asian tradition.

Pandan Wangi is an outstanding pummelo variety from Java's Bativia district. It has a thick rind with a faint yellow-green hue and a meaty pith. The blush red pulp has up to eighteen segments and as many seeds. The fruit yields very little juice of a complex flavour but it is pleasant and sweet with a hint of lime.

Pink Pomelo is a pigmented member of the Thai group. Although it is sometimes bitter, it can have some of the best flavour of all the California pomelos. The rind is medium thick and slightly pebbly and looks much like the pink grapefruit. It has bright yellow skin, a juicy pulp, and many seeds; but it is less acidic than a grapefruit.

Red Shaddock was only recently developed in Africa at Tambuti Estate in Swaziland. It has an extraordinary flavour that is low in acid leaving a sugary sweet aftertaste. Red Shaddock pulp is very similar to that of the Star Ruby, crisp and intensely red, but has many seeds. The rind is a grapefruit-yellow colour and is smooth. It is ideal for cooking into various recipes.

Siamese Sweet was introduced into the US in 1930 by the USDA and grown at the University of California's Citrus Research Center in Riverside. The fruit is large and oblique, with a somewhat pebbly grapefruit-like rind. The flesh is white and meaty and has few seeds. Despite its name, the mild juice is faintly bitter. In Thailand, this pomelo is picked when it loses its green colour, and then stored indoors for a few months to improve its flavour and juiciness.

Wainwright is a California fruit that probably descended from the Chinese group. It is a large collared fruit, with a lemon-lime coloured rind that tapers characteristically, moderately thick, but soft and easy to peel. The flesh has up to fourteen juicy segments and has a pleasant flavour, but it is heavily seeded.