Babylon English Dictionary
remove impurities; remove the foul membrane from the surface of a liquid; form a foul membrane, become covered with a dirty film
Webster's Revised Unabridged Dictionary (1913)
(p. pr. & vb. n.)
The act of taking off scum.
That which is scummed off; skimmings; scum; -- used chiefly in the plural.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter. About