As I mentioned on Monday, the Chinese character for "bun" is 包 (bāo).
Although some types of 包, such as the Shanghai 小籠包 (xiǎo lóng bāo) mentioned below, are translated into English using the term "dumpling", this is something of a misnomer, as 包 aren't really considered to be dumplings in Chinese cuisine. The generic Chinese term for "dumpling" is 餃子 (jiǎo zi), while the generic term for "bun" is 包子 (bāo zi). There's a long and somewhat confusing thread on this subject on Chowhound.
As far as I can make out, the essential difference between 包子 and 餃子 lies in the method of wrapping, though both types of wrapper start out as a flat circle of some kind of dough. 包子 are sealed by pulling up the edges of the circle evenly around and then twisting and pinching at the top, leaving a sort of characteristic "topknot". Conversely, 餃子 wrappers are folded by bringing one half of the circle to meet the other (sort of like folding it in half) and then either pleated along one side or simply sealed flat.
There is quite some variation within the 包子 type (as well as within the 餃子 type, though that's a subject for another post).
One type of 包 that you might see on a dim sum menu is the 上海小籠包 (Shànghǎi xiāo lóng bāo), often translated into English as "soup dumpling". Shanghai-style 小籠包 are sealed in the 包子 style, but have unleavened wheat dough wrappers; this type of wrapper is more commonly associated with 餃子, hence the linguistic confusion mentioned above. The best examples include a few small cubes of jellied stock along with the minced pork filling, which melt on steaming and fill the mouth with a gush of delicious hot soup on eating — this is where the English term "soup dumpling" comes from (photo [not mine] of Shanghai 小籠包).
Sichuan-style 小籠包, on the other hand, have breadier, leavened wrappers and are filled with shredded pork seasoned with soy sauce — no soup (photo of Sichuan 小籠包). These are not dim sum items as the term is generally understood in the UK, but rather snacks or 小吃 (xiǎo chī, literally "small eats").
I'm pretty sure that the first type of 包 I ever learned about was 叉燒包 (chā shāo bāo), or cha siu bao in the more common Cantonese pronunciation. These are soft, fluffy, slightly sweet buns filled with barbecued pork; many people consider them a must-have item on dim sum outings. 叉 (chā) means "fork" or "prong", and 燒 means "cook" or "roast", so the name is a reference to the traditional method of skewering the pork on a long fork before roasting it.
包 on a menu doesn't always mean "bun"; sometimes its other meaning of "package" or "bundle" is the intended one. An example of this is 海鮮生菜包 (hǎi xiān shēng cài bāo), or lettuce-wrapped seafood; a savoury mixture of chopped seafood served with lettuce leaves to wrap it up in.
Here are some other dishes with 包 in the name:
|奶黃包||nǎi huáng bāo||custard bun (a popular dessert at dim sum)|
|鍋包肉||guō bāo ròu||Dongbei-style sweet and sour pork|
|紙包蝦||zhǐ bāo xiā||paper-wrapped prawns|
|手撕包菜||shǒu sī bāo cài||hand-torn cabbage|
|包:||bāo||radical 20 (勹)||Cantodict||MandarinTools||YellowBridge||Zhongwen|