Biol. a whiplike part or process of some cells, esp. of certain bacteria, protozoans, etc., that is an organ of locomotion or produces a current in the surrounding fluid
Bot. a threadlike shoot or runner
Zool. the terminal, lashlike portion of the antenna in many insects
Origin:
L, a whip: see flagellate
See flagellum in American Heritage Dictionary 4
nounpl.fla·gel·la(-jĕlˈə)
Biology A long, threadlike appendage, especially a whiplike extension of certain cells or unicellular organisms that functions as an organ of locomotion.