pond scum

pond scum

n.

Any of various freshwater algae that form a usually greenish film on the surface of stagnant water.

Thesaurus

Noun

1.

pond scum - free-floating freshwater green algae chlorophyte, green algae - algae that are clear green in color; often growing on wet ricks or damp wood or the surface of stagnant water family Zygnemataceae, Zygnemataceae - pond scums: common freshwater algae forming green slimy masses