The lecture investigates the process that led to definition of 'Colon Classification' (1925) and 'Apupa pattern' (1951). Among the most significant hypotheses and with more evidence, we report what the term umbral might be related to the work that the Indian mathematician Srinivasa Ramanujan did a few years before in Cambridge on mathematical notations so-called umbral calculus. The way C.S.Peirce describes these notations, suggests cross-references to faceted-classification: In other mathematics, they have no existence in the universe of quantity. But joined together in sets they do. They are just like chemicals radicals, each having a certain number of unsatisfied wants. When each of these is satisfied by union with another, the completely saturated whole has an existence in the universe of quantity.