Etymology of the English word rubiginous
the English word rubiginous
derived from the Latin word rubiginosus
derived from the Latin word rubigo (rust; mildew, blight)
derived from the Latin word robus (mainstay, bulwark, source of strength; military strength, might, power; oak; red; red; strength, firmness, solidity)
derived from the Proto-Indo-European root *reudh-
derived from the Latin word robigo (rust; mildew, blight)