onychomancy en · NOUN
Etymology
From onycho- + -mancy.
Meanings
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(uncountable) An ancient form of divination based on the symbols that are reflected by sunlight on a person's fingernails.
I am still not sure what to make of this treatise on onychomancy, that is, divining by observing the fingernails, except that he accounted for the practice as an example of the acute application of observational technique to the signs and symbols left by intelligent nature for humans to decipher in view of some benefit.
2016, Brendan Dooley, Angelica's Book and the World of Reading in Late Renaissance Italy: