noun Biology. a buoyant mat of weeds,
algae, and associated organisms that floats on or near the surface of a lake, river, or other body of fresh water.
Origin: 1940–45; pleus- (<
Greek pleûs(
is) sailing, or
pleus- aorist stem of
pleîn to sail, go by sea) +
-ton, on the model of
nekton,
plankton Related forms