carapace

Etymology

Borrowed from French carapace (“tortoise shell”), from Spanish carapacho, of unknown origin, but likely from an extinct Ibero-Mediterranean substrate language. Compare Catalan carabassa, Ancient Greek κάραβος (kárabos, “beetle”), Latin scarabaeus (the source of scarab); also Spanish galápago (“kind of turtle”). Doublet of calipash.

noun

1. A hard protective covering of bone or chitin, especially one which covers the dorsal portion of an animal.
2. in figurative use
   So, little by little, youth loosens the hard carapace of confining custom their elders have built over the human heart. 1928, Edward A. Ross, World Drift, New York, London: The Century Co., page 12
   This is all a massive failure of science to pierce the carapace of public ignorance. January 8 2010, Simon Jenkins, “The proliferation of nuclear panic is politics at its most ghoulish”, in The Guardian, §: “Comment & Debate”, page 29, column 4