Ferrule Share definition Flag The protective point or knob on the far end of an umbrella, or parasol. He jabbed the man in the neck with the ferrule of his umbrella. It was quite sharp, because his umbrella has a concealed blade in it. Ferrule by TanorFaux October 18, 2012 0 0 Get merch Get the Ferrule mug. Buy Now — $32.95 See more merch