What does "skim" mean?

Additional senses

1. 2.To pass near the surface of; to brush the surface of; to glide swiftly along the surface of. Homer describes Mercury as flinging himself from the top of Olympus, and skimming the surface of the ocean. Hazlitt.
2. 3.Fig.: To read or examine superficially and rapidly, in order to cull the principal facts or thoughts; as, to skim a book or a newspaper.
3. 4.To pass lightly; to glide along in an even, smooth course; to glide along near the surface. Not so when swift Camilla scours the plain, Flies o'er the unbending corn, and skims along the main. Pope.
4. 5.To hasten along with superficial attention. They skim over a science in a very superficial survey. I. Watts.
5. 6.To put on the finishing coat of plaster.
6. 7.Contraction of Skimming and Skimmed. Skim coat, the final or finishing coat of plaster. -- Skim colter, a colter for paring off the surface of land. -- Skim milk, skimmed milk; milk from which the cream has been taken.
7. 8.Scum; refuse. Bryskett.