What is the origin of integument?

Integument, “covering, coating,” comes straight from Latin integumentum “covering, shield, guard, wrapping,” a derivative of the verb integere “to cover, overlay,” itself a compound of the preposition and prefix in, in– “in, on, upon” and the simple verb tegere “to cover, close, bury.” Tegere comes from the Proto-Indo-European root (s)teg-, (s)tog– “to cover.” The variant teg– forms Latin tēgula “a roof tile” (source of English tile). The variant tog– yields Latin toga “toga” (the loose outer garment worn by Roman male citizens in public). The variant (s)teg– yields stégē “covering” and stégos “roof” in Greek, which in turn forms the first element of English stegosaurus, literally “roofed or covered lizard” (from the row of bony plates along its back). Integument entered English in the first half of the 17th century.