Rarefy v. t. (past & past part. rarefied; pres. part. rarefying) To make rare, thin, porous, or less dense; to expand or enlarge without adding any new portion of matter to; opposed to condense.
... try in vain to slay Truth with the steel or the stake, but error falls only before the sword of Spirit. 37:9 Martyrs are the human links which connect one stage with another in the history of religion. They are earth's lumi- naries, which serve to cleanse and rarefy the atmosphere of 37:12 material sense and to permeate humanity with purer ideals. Consciousness of right-doing brings its own reward; but not amid the smoke of battle is merit seen and ... — Science and Health With Key to the Scriptures • Mary Baker Eddy