bulb
A rounded underground plant part that stores food and energy.
A bulb is the rounded underground part of certain plants that stores food and energy, allowing the plant to survive through winter or dry seasons and grow again when conditions improve. When you plant a tulip or daffodil bulb in fall, you're essentially planting a complete plant in a compact, dormant package. Come spring, that bulb uses its stored energy to push up green shoots and colorful flowers.
If you slice a bulb in half, you'll see layers wrapped around each other, like an onion (which is itself a type of bulb). These layers are actually modified leaves packed with nutrients. Garlic, onions, and shallots are all bulbs we eat, which is why they have that layered structure and taste so rich and flavorful.
The word also refers to the glass part of a lamp that produces light. A light bulb has that distinctive rounded shape, somewhat like a plant bulb, which is how it got its name. When someone has a sudden good idea, we sometimes draw a light bulb over their head in cartoons, symbolizing that flash of insight or inspiration.