Il nome non ha una derivazione precisa. L'etimologia, secondo alcuni, fa pensare alla parola napoletana prova-provola con cui in Campania viene indicato il classico latticino di bufala a pasta filata, da consumarsi fresco. ["Dieta Mediterranea"]The peculiarity of prudery is to multiply sentinels, in proportion as the fortress is less threatened. [Victor Hugo, "Les Misérables"]
Some 20c. writers in English used extended form prudibundery, in many cases likely for contemptuous emphasis, from French prudibonderie "prudery."
All in all, it seems that Prussian blue was synthesised for the first time around 1706 by the Swiss immigrant Johann Jacob Diesbach in Berlin. [Jens Bartoll and Bärbel Jackisch, "Prussian Blue: A Chronology of the Early Years," "Zeitschrift für Kunsttechnologie und Konservierung" 24, No. 1, 2010]
Early German sources refer to it as Preußisches Ultra-Marin and berliner blau. Prussic acid (1790), is from French acide prussique, so called in reference to prussian blue pigment, to which it is chemically related.