What does "winnow" mean?

Winnow: 2. To sift, as for the purpose of separating falsehood from truth; to separate, as had from good. Winnow well this thought, and you shall find This light as chaff that flies before the wind. Dryden.

Additional senses

  1. 2.To beat with wings, or as with wings.[Poetic] Now on the polar winds; then with quick fan Winnows the buxom air. Milton.
  2. 3.To separate chaff from grain. Winnow not with every wind. Ecclus. v. 9.

Sources