flagellum

American  

[fluh-jel-uhm] / fləˈdʒɛl əm /

noun

flagella, plural flagellums plural

1. Biology. a long, lashlike appendage serving as an organ of locomotion in protozoa, sperm cells, etc.

2. Botany. a runner.

3. Also called clavola.  Entomology. (in an antenna) the whiplike portion above the basal joints.

4. a whip or lash.

---

flagellum British  

/ fləˈdʒɛləm /

noun

1. biology a long whiplike outgrowth from a cell that acts as an organ of locomotion: occurs in some protozoans, gametes, spores, etc

2. botany a long thin supple shoot or runner

3. zoology the terminal whiplike part of an arthropod's appendage, esp of the antenna of many insects

---

flagellum Scientific  

/ flə-jĕl′əm /

flagella plural

1. A slender whiplike part extending from some single-celled organisms, such as the dinoflagellates, that moves rapidly back and forth to impart movement to the organism.

---

Other Word Forms

Derived Forms

• flagellar
  adjective

Inflected Forms

Nouns

• flagella
  plural
• flagellums
  plural

Etymology

Origin of flagellum

1800–10; < Latin: whip, lash, diminutive of flagrum a whip, scourge

Explanation

A flagellum is part of a cell, a sort of thread that helps the cell move around by moving like a whip. Bacteria are among the cells that can have flagella. In a bacterial cell, a flagellum twists in a circle like a screw, while in a eukaryote (a plant or animal cell), the flagellum moves in more of an S motion. These long, lash-like appendages propel cells forward, but they also help them sense temperature changes and the presence of certain chemicals. In Latin, flagellum means "whip," from a Proto-Indo-European root meaning "to strike."

Example Sentences

See Examples For:

flagellum flagella

The flagellum comprises more than 30 distinct parts, so similar to those of an outboard motor that biologists speak of the flagellum’s propeller, drive shaft and so forth.

From The Wall Street Journal ● Apr. 16, 2026

Some of the most revealing genetic losses involved genes responsible for forming the tail, or flagellum, of sperm.

From Science Daily ● Jan. 31, 2026

All five isolates exhibited a distinctive feature of Minorisa, a single flagellum coiled spirally around the cell.

From Science Daily ● Oct. 26, 2023

Within 24 hours, the fungus can produce thousands more spores that are released back into the water, where they swim using a threadlike structure called a flagellum.

From Washington Post ● Mar. 15, 2023

Black; closely and strongly punctured; the clypeus, a line on the mandibles, and the scape in front, yellow; tips of the mandibles, the scape above, and the base of the flagellum ferruginous.

From Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology by Various

Moist environments such as gut mucus, wound fluids, or the urinary tract provide surfaces where bacteria could spread through swashing, even when their flagella are not functioning effectively.

From Science Daily ● Mar. 13, 2026

To keep up with their shorter kin, the researchers found, longer bacteria grow a greater number of flagella and disperse their swimming loads among these bundles of limbs.

From Science Magazine ● Dec. 7, 2023

Even life itself depends critically on turbines for fundamental processes, such as the FoF1-ATP synthase that produces fuels for biological cells and the bacterial flagella motor that propels bacteria.

From Science Daily ● Oct. 26, 2023

Some have flagella and swim up through the snow in spring, when temperatures warm and enough meltwater is present for the cells to photosynthesize and explode in numbers.

From Seattle Times ● Jul. 21, 2023

The affinities of the Dinoflagellata are certainly with those Cryptomonadine Flagellates which possess two unequal flagella; the zoospores or young of the Cystoflagellates are practically colourless Dinoflagellates.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5 "Dinard" to "Dodsworth" by Various