bulb

1. N-COUNT A bulb is the glass part of an electric light or lamp, which gives out light when electricity passes through it. 電燈泡

The stairwell was lit by a single bulb. 樓梯間只有一盞燈照明。

2. N-COUNT A bulb is a root shaped like an onion that grows into a flower or plant. 球莖

...tulip bulbs. …郁金香球莖。