‘洋葱’ (yáng cōng) literally means ‘ocean leek’—‘洋’ (yáng) historically refers to things foreign or ocean-related, and ‘葱’ (cōng) is the general term for scallions and alliums. This name reflects its origin: onions were introduced to China from Central Asia via ancient trade routes, so they were perceived as ‘foreign leeks.’ Today, 洋葱 specifically refers to the common bulb onion (Allium cepa), distinguished from native green onions (葱, cōng) or Welsh onions (葱 or 葱头).

The word is used in cooking, agriculture, and everyday conversation. It appears in recipes, market lists, and health discussions—often noted for its pungent aroma, layered bulb structure, and culinary versatility (e.g., stir-fried, pickled, or raw in salads). Unlike the broader term 葱, which can refer to several green alliums, 洋葱 always denotes the round, papery-skinned, underground-bulb variety.