Integument

integument [ĭn-TEG-yuh-mənt]
n. 1. a natural covering, as a skin, shell, or rind; 2. any covering, coating, enclosure, etc.

[From Latin in- + tegere ("to cover")]

Though it's not used too commonly in its figurative sense, integument is essentially a high-priced synonym for cover or covering. As technical jargon, science writers use integument and integumentary literally to mean skin, shell, plant rinds, etc. Tegmen ("a cover, covering, or integument") and tegument ("a covering or vestment") mean essentially the same thing and share the same Latin etymology.

The closely spelled integer, integrity and integral don't have the same etymology as integument. Integer derives from in- (meaning "not") + tangere (meaning "touched"). Integer, of course, means whole.

In an essay in The Atlantic, "The Revenge of Karl Marx," Christopher Hitchens uses integument as a figurative synonym for cover:

What (Marx) postulated, and what made him different from any previous theorist of materialism whether historical or dialectical, was a sharp distinction between the forces and the relations of production. Within the integument of one system of exploitation, in other words, was contained a systemic conflict that, if not resolved, would lead to stagnation and decline but, if properly confronted, might lead to a higher synthesis of abundance and equality.

In "An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures," published in Nature, Xiao-Ting Zheng and his colleagues describe the peculiar outer skin structure of a dinosaur called Tianyulong (see picture above):

More surprisingly, Tianyulong bears long, singular and unbranched filamentous integumentary (outer skin) structures. This represents the first confirmed report, to our knowledge, of filamentous integumentary structures in an ornithischian dinosaur.