酸 (suān) is the Chinese character for "sour". On menus, this often appears in combination with 辣 (là/spicy), for example as 酸辣湯 (suān là tāng), or hot and sour soup. Note that the Chinese is the other way around from the English, as the literal translation is "sour and spicy soup" — this also applies to other hot and sour items, such as 酸辣土豆絲 (suān là tǔ dòu sī), which is hot and sour shredded potato.
Another frequent partner to 酸 is 菜 (cài). In this context, 菜 means "vegetable", though 酸菜 is often translated as "pickled greens"; it's a tasty, sour, crunchy pickle made from 芥菜 (jiè cài), or mustard greens. Food Mayhem has a recipe for making your own, but you can buy it in jars too, either chopped or whole. I've discussed 酸菜 before, in my post on 酸菜魚/suān cài yú (fish soup with pickled greens).
Here are some more dishes with 酸 in the name:
|酸辣豆花||suān là dòu huā||sour-and-hot "flower" beancurd (extra-soft beancurd)|
|酸菜肉絲麵||suān cài ròu sī miàn||noodles [麵] with shredded [絲] pork [肉] and pickled greens [酸菜]|
|甜酸炸雲吞||tián suān zhà yún tūn||deep-fried [炸] sweet-and-sour [甜酸] wontons [雲吞]|
|酸豆角炒肉泥||suān dòu jiǎo chǎo ròu ní||stir-fried [炒] pickled green beans [酸豆角] with minced [泥] pork [肉]|
|酸:||suān||radical 164 (酉)||Cantodict||MandarinTools||YellowBridge||Zhongwen|