Motility's a biological term which refers to the ability to move spontaneously and actively, consuming energy in the process. It can apply to either single-celled or multicellular organisms. Motile marine animals are commonly called free-swimming. The opposite of motility's sessility. Examples of motility include: Sperm cells, propelled by the regular beat of their flagellum The bacterium E. coli, which swims by roting a helical prokaryotic flagellum In cellular biology or biomedical engineer… (More on Motile)