nodule

American  

[noj-ool] / ˈnɒdʒ ul /

noun

nodules plural

1. a small node, knot, or knob.

2. a small, rounded mass or lump.

3. Botany. a tubercle.

---

nodule British  

/ ˈnɒdjuːl /

noun

1. a small knot, lump, or node

2. Also called: root nodule.  any of the knoblike outgrowths on the roots of clover and many other legumes: contain bacteria involved in nitrogen fixation

3. anatomy any small node or knoblike protuberance

4. a small rounded lump of rock or mineral substance, esp in a matrix of different rock material

---

nodule Scientific  

/ nŏj′o̅o̅l /

1. A small, usually hard mass of tissue in the body.

2. A small, knoblike outgrowth found on the roots of many legumes, such as alfalfa, beans, and peas. Nodules grow after the roots have been infected with nitrogen-fixing bacteria of the genus Rhizobium.

3. See more at legume

4. A small, rounded lump of a mineral or mixture of minerals that is distinct from and usually harder than the surrounding rock or sediment. Nodules often form by replacement of a small part of the rocks in which they form.

---

Other Word Forms

Derived Forms

• nodular
  adjective

Inflected Forms

Nouns

• nodules
  plural

Etymology

Origin of nodule

1590–1600; < Latin nōdulus a little knot, equivalent to nōd ( us ) node + -ulus -ule

Explanation

A nodule is a small, raised bump under the skin. You might notice a nodule on the top of your foot after spraining your ankle. Any solid bump or node that you can feel just beneath your skin is a nodule. You may have noticed nodules in your neck when you have a sore throat or a nodule on your shin where you bumped it into the coffee table. Another kind of nodule is very similar, but appears on a plant's surface. The Latin root word is nodulus, "small knot," from nodus, or "knot."

Example Sentences

See Examples For:

nodule nodules

The same AI pattern-recognition that’s learning to spot breast tumors is being applied to thyroid screening, lung nodule detection and colonoscopies.

From The Wall Street Journal ● May 4, 2026

The leftover sediment and fine nodule fragments are then released back into the ocean.

From Science Daily ● Nov. 8, 2025

The diagnosis occurred last week, following a urinary screening that revealed a small nodule in his prostate, which revealed the aggressive Stage 4 prostate cancer, according to the statement.

From Slate ● May 20, 2025

Biden said his diagnosis was made on Friday after he reported urinary symptoms which led doctors to find a small nodule on his prostate.

From BBC ● May 19, 2025

“Right,” he said, and gripped a golden nodule that protruded from the trunk.

From "Impossible Creatures" by Katherine Rundell

"It was her leg which was stuck within a rock cleft, and there was some space around the side of it and also nodules of rock which were stopping it from coming out," Rees said.

From BBC ● Jun. 27, 2026

Before, Ahmad could tap — meaning to cut incisions in the acacia trees, which exude sap that a few weeks later hardens into nodules of Hashab gum — four orchards in one go.

From Los Angeles Times ● May 31, 2026

Ion is tailored for procedures in the lung, typically to sample suspicious nodules or legions as part of a cancer diagnosis.

From Barron's ● Apr. 21, 2026

The rover also spotted small, bumpy structures called nodules.

From Science Daily ● Mar. 14, 2026

The nitrogen-fixing rhizobia in root nodules, the mycetomes of insects, and the enzyme-producing colonies in the digestive tracts of many animals are variations of this meticulously symmetrical symbiosis.

From "The Lives of a Cell" by Lewis Thomas

Related Words

• growth
• knot
• node