Definitions

1. noun

a type of seaweed or algae, especially a type that forms a scum on the surface of the water

“The beach was covered in scallage after the recent storm.”

2. noun

a type of scum or foam that forms on the surface of a liquid, especially a type that is composed of algae or other microorganisms

“The scallage on the surface of the water was a sign of the pollution in the river.”