flagellum

/ˈflæˌdʒɛləm/

Other forms: flagella

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."

Definitions of flagellum

1. noun

   a lash-like appendage used for locomotion (e.g., in sperm cells and some bacteria and protozoa)
   type of:

   appendage, outgrowth, process

   a natural prolongation or projection from a part of an organism either animal or plant
2. noun

   a whip used to inflict punishment (often used for pedantic humor)
   synonyms: scourge

   type of:

   whip

   an instrument with a handle and a flexible lash that is used for whipping