lobe

American  

[lohb] / loʊb /

noun

1. a roundish projection or division, as of an organ or a leaf.

2. earlobe.

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lobe British  

/ ləʊb /

noun

1. any rounded projection forming part of a larger structure

2. any of the subdivisions of a bodily organ or part, delineated by shape or connective tissue

3. short for ear lobe

4. any of the loops that form part of the graphic representation in cylindrical coordinates of the radiation pattern of a transmitting aerial Compare radiation pattern

5. any of the parts, not entirely separate from each other, into which a flattened plant part, such as a leaf, is divided

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lobe Scientific  

/ lōb /

1. A rounded projection, as on a leaf or petal. The leaves of many oak species have prominent lobes.

2. An anatomical division of an organ of the body. The liver, lungs, and brain are all characterized by lobes that are held in place by connective tissue.

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Other Word Forms

• multilobe noun

Etymology

Origin of lobe

1515–25; < Medieval Latin lobus ( Late Latin: hull, husk, pod) < Greek lobós, akin to Latin legula lobe of the ear

Example Sentences

However, the widely repeated claim that brain development, especially in the frontal lobe, stops at 25 is not accurate.

From Science Daily • Feb. 19, 2026

“I think there’s something to be said for frontal lobe development,” she says.

From Los Angeles Times • Jan. 25, 2026

In typical cases, the exposure damages the brain’s frontal lobe, which slows cognition, impairs impulse control, restricts dopamine production and affects mood.

From The Wall Street Journal • Dec. 22, 2025

I feel like—and I think it comes with turning 25—but my frontal lobe has developed and it’s like, “All right, time to be an adult now.”

From Slate • Dec. 11, 2025

He came back to the desk, knelt down beside it, real close, and flapped his lobe out so it sat like a tiny pancake on the top edge of the desk.

From "Fourth Grade Rats" by Jerry Spinelli