†b.of main white: mainly white, principally white (Skeat). Obsolete.The construction here is obscure and appears to be unparalleled; it seems unlikely at this date that manen.1 is intended, and such a reading would not improve the sense.
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?1530 J. FitzherbertBk. Husbandry (rev. ed.) f. xxxv Put..to your coloured mares of mayne whyte a horse of coloure of mayne whyte.