어원: Calque of Ancient Greek εἰς ὄνῠχᾰ (eis ónukha, literally “to a nail”): an expression borrowed from sculptors, who, in modelling, give the finishing touch with the fingernail, or from joiners, who test the accuracy of joints in wood by the fingernail.

뜻

1. to a hair, to a nicety, precisely, exactly, with great exactitude, to an exact measurement or standard, perfectly