Plankton \Plank"ton\ (pl[a^][ng]k"t[o^]n), n. [NL., fr. Gr. plagto`n, neut. of plagto`s wandering, pla`zesqai to wander.]

(Biol.) All the animals and plants, taken collectively, which live at or near the surface of salt or fresh waters. -- Plank*ton"ic, a.

Source: Webster's Revised Unabridged Dictionary (1913)