Merriam-Webster Collegiate Dictionary - flagellate

 I. transitive verb  (-lated; -lating)  Etymology: Latin flagellatus, past participle of flagellare, from flagellum, diminutive of flagrum whip; perhaps akin to Old Norse blaka to wave  Date: circa 1623  1. whip, scourge  2. to drive or punish as if by whipping  II. adjective  Etymology: New Latin flagellatus, from flagellum  Date: circa 1859  1.  a. (or ~d) having flagella  b. shaped like a flagellum  2. ~ (III) of, relating to, or caused by ~s ~ diarrhea  III. noun  Etymology: New Latin Flagellata, class of unicellular organisms, from neuter plural of flagellatus  Date: 1879 a ~ protozoan or alga