In botany, a bulb is a modified leaf bud that sprouts roots from its base. It comprises fleshy leaf scales that store a reserve supply of food, allowing the plant to survive adverse weather conditions. See onion, and lily. All true lilies have bulbs or corms. See lily family.

Compare with corm[?], rhizome, or tuber.

Bulb is one of the very few words in the English language that doesn't rhyme with anything. See List of English words without rhymes.