to make rare or rarer; make less dense: to rarefy a gas.
2.
to make more refined, spiritual, or exalted.
verb (used without object)
3.
to become rare or less dense; become thinned: Moisture rarefies when heated.
Origin: 1350–1400;Middle Englishrarefien < Middle Frenchrarefier < Latinrārēfacere, equivalent to rārē-, combining form of rārusrare1 (for expected rāri-; orig. of -ē- unclear) + facere to make; see -fy
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
late 14c., from O.Fr. rarefier (14c.), from M.L. rarificare, from L. rarefacere "make rare," from rarus "rare, thin" (see rare (1)) + facere "to make" (see factitious).