cradle (n.) "baby's bed," usually mounted on rockers or suspended for rocking or swinging, c. 1200, cradel, from Old English cradol "little bed, cot," from Proto-Germanic kradulaz "basket" (source also of Old High German kratto, krezzo "basket," German Krätze "basket carried on the back").| vault (n.) "arched roof or ceiling," c. 1300, vaute, from Old French voute "arch, vaulting, vaulted roof or chamber," from Vulgar Latin volta, contraction of volvita, noun use of fem. of volvitus, alteration of Latin volutus "bowed, arched," past participle of volvere "to turn, turn around, roll," from PIE root wel- "to turn, revolve." The -l- appeared in English c. 1400, an etymological insertion in imitation of earlier forms.