bulb

The word “bulb” means the rounded glass part of an electric light that produces light when current passes through it. In plain terms, either the glass part of a lamp that lights up, or the round underground part of certain plants.

“Bulb” is pronounced BUHLB (/ˈbʌlb/ in IPA).

Here is “bulb” used in a sentence: “The bulb in the hallway needs replacing.”

“Bulb” is a noun.

The word “bulb” comes from Ancient Greek. From Latin bulbus, "bulb, onion," from Ancient Greek bolbos, a round-stemmed plant.

“Bulb” is an uncommon word in modern English, usually learned at around the A2 level.

“Bulb” has 2 distinct senses listed in this dictionary. The most common is: the rounded glass part of an electric light that produces light when current passes through it.

Both forms are used: "light bulb" as two words is the more traditional style, while "lightbulb" as one word is increasingly common, especially in American English. Either way, it refers to the rounded glass part of an electric light that produces light when current passes through it.

A bulb is a rounded underground plant part made of a short stem and layered fleshy leaves, from which a new plant grows, while a corm is a solid, swollen stem base without that layered structure, and a tuber, like a potato, is a swollen underground stem or root that stores food.

An incandescent bulb produces light by heating a filament until it glows, while an LED bulb produces light through a semiconductor and uses far less energy. Both are still bulbs in the sense of producing light when current passes through them.