1. A part resembling an arched roof or dome, the pharyngeal vault or fornix, the nonmuscular upper part of the nasopharynx; the palatine vault, arch of the plate; vault of the vagina, fornix of vagina. 2. A type of particle that weighs about 13 Mda; among the largest ribonucleoprotein particles present in eukaryotic cells. It is usually found in the vicinity of nuclear pores. The hollow configuration suggests role as central transporter of the nuclear pore complex.