Mastigophora

thumb|"Flagellata" from Ernst Haeckel's Artforms of Nature, 1904 thumb|Parasitic Excavata (Giardia lamblia) thumb|Green algae ([[Chlamydomonas)]]

A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word flagellate also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, several derivations of the term "flagellate" (such as "dinoflagellate" and "choanoflagellate") are more formally characterized.