What is the meaning of Flagellum?

In protists, a long, whiplike membrane-enclosed organelle used for locomotion or feeding.

In bacteria, a long, whiplike proteinaceous appendage, used for locomotion.

A whip

flagellum

flagellum (whip)

whip, lash, scourge

whip for driving animals (riding horses, cattle etc.)

tentacle

young branch, shoot

Source: wiktionary.org