What is another word for "vacuum"?

Roget's Thesaurus (1911) lists these synonyms for "vacuum": adust, aeration, aerial, aerification, aeriform, aerodynamics, aerostatics, air, airy, alkali, ammonia, ammoniacal, anhydrous, arefaction, arid, aridity, biscuit, bladder, blow, bone, chemical, clothes, clothesline, cloud, dehydrate, dephlegmation, desiccate, desiccation, desiccative, device, diffuse, drain, drainage, dried, drier, drought, dry, drying, dryness, dust.