(also intr) to remove colour from, or (of colour) to be removed; whiten; fade: the sun blanched the carpet; over the years the painting blanched
2.
(usually intr) to become or cause to become pale, as with sickness or fear
3.
to plunge tomatoes, nuts, etc, into boiling water to loosen the skin
4.
to plunge (meat, green vegetables, etc) in boiling water or bring to the boil in water in order to whiten, preserve the natural colour, or reduce or remove a bitter or salty taste
5.
to cause (celery, chicory, etc) to grow free of chlorophyll by the exclusion of sunlight
6.
metallurgy to whiten (a metal), usually by treating it with an acid or by coating it with tin
7.
to attempt to conceal something
[C14: from Old French blanchir from blanc white; see blank]
"to make white, turn pale," late 14c., from O.Fr. blanchir "to whiten, wash," from blanc "white" (11c.; see blank). Originally "to remove the hull of (almonds, etc.) by soaking." Intransitive sense of "to turn white" is from 1768.
blanch
"to start back, turn aside," 1570s, variant of blench (q.v.).