Whiten, v. t.
To make white; to bleach; to blanch; to whitewash; as, to whiten a wall; to whiten cloth. The broad stream of the Foyle then whitened by vast flocks of wild swans. Macaulay.
Syn. -- See Blanch.
1 other Webster entry under this spelling
Whiten, v. i. [imp. & p. p. Whitened; p. pr. & vb. n. Whitening.]
To grow white; to turn or become white or whiter; as, the hair whitens with age; the sea whitens with foam; the trees in spring whiten with blossoms.
Shades of meaning
Fernald has no entry of its own for whiten; he lists it under bleach.
Where he writes about it:
To whiten is to make white in general, but commonly it means to overspread with white coloring-matter. — from bleach
Bleach and blanch both signify to whiten by depriving of color, the former permanently, as linen; the latter either permanently (as, to blanch celery) or temporarily (as, to blanch the cheek with fear). — from bleach
To whitewash is to whiten superficially, especially by false approval. — from bleach