[ flə'dʒɛləm ]
■ noun ( plural flagella ) Biology a slender thread-like structure, especially a microscopic whip-like appendage which enables many protozoans, bacteria, spermatozoa, etc. to swim.
Derivatives
flagellar adjective
Origin
C19 (denoting a whip or scourge): from L., dimin. of flagrum 'scourge'.