Topic - Onion

The onion is any of a variety of plants in the genus Allium, specifically Allium cepa. Allium cepa is also known as the "garden onion" or "bulb" onion. Above ground, the onion shows only a single vertical shoot; the bulb grows underground, and is used for energy storage, leading to the possibility of confusion with a tuber, which it is not. It is a close relative to garlic. - Source: Wikipedia