flagellum

noun

fla·​gel·​lum flə-ˈje-ləm 

plural flagella flə-ˈje-lə  also flagellums

: any of various elongated filiform appendages of plants or animals: such as

a

: the slender distal part of an antenna

b

: a long tapering process that projects singly or in groups from a cell and is the primary organ of motion of many microorganisms

Examples of flagellum in a Sentence

Recent Examples on the Web

Scientists in the 1980s and ’90s figured out that when the C ring rotates, the flagellum does too. — Quanta Magazine, 20 Apr. 2026

Protein role in sperm development Inside every flagellum is an incredibly complex structure, including tiny components called radial spokes. — Mrigakshi Dixit, Interesting Engineering, 11 Sep. 2025

This means that the flagellum has a fool-proof mechanism to enable swimming in low viscosity environments, which would otherwise be impossible for aquatic species. — Laura Baisas, Popular Science, 27 Sep. 2023

Microscopic examinations revealed the spore surface is lined with rows of proteins called rodlins that may grab a passing flagellum—working much like Velcro. — Elizabeth Pennisi, Science | AAAS, 22 Mar. 2021

Word History

Etymology

New Latin, from Latin, whip, shoot of a plant

First Known Use

1852, in the meaning defined above

Rhymes for flagellum

• coelom
• labellum
• scutellum
• antebellum
• cerebellum
• bellum
• pelham
• vellum
• velum

Kids Definition

flagellum

noun

fla·​gel·​lum flə-ˈjel-əm 

plural flagella -ˈjel-ə  also flagellums

: a long whiplike structure by which some tiny plants and animals move

flagellar

-ˈjel-ər

adjective

Medical Definition

flagellum

noun

fla·​gel·​lum flə-ˈjel-əm 

plural flagella -ə  also flagellums

: a long tapering process that projects singly or in groups from a cell and is the primary organ of motion of many microorganisms