Pronunciation: ' pr ə -sh ə n-
Function: noun
Etymology: Prussia, Germany
Date: 1724
1 : any of numerous blue iron pigments formerly regarded as ferric ferrocyanide
2 : a dark blue crystalline hydrated ferric ferrocyanide Fe 4 [ Fe(CN) 6 ] 3 · x H 2 O used as a test for ferric iron
3 : a greenish blue