exorcism [ek-sawr-siz-uh m, -ser-] WORD ORIGIN noun the act or process of. the ceremony or the formula used in : An elaborate exorcism was pronounced over the sick man.
Origin of exorcism 1350–1400; Middle English exorcisme (Old French) Medieval Latin Greek exorkismós administration of an oath. See, Related formsex·or·cis·mal [ek-sawr-siz-muh l, ‐ser] /ˌɛk sɔrˈsɪz məl, ‐sər/, ex·or·ci·so·ry [ek-sawr-sahy-zuh-ree, ‐ser] /ˈɛk sɔrˈsaɪ zə ri, ‐sər/, ex·or·cis·ti·cal, ex·or·cis·tic, adjective Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019 Word Origin and History for exorcistic exorcism n.
early 15c., “a calling up or driving out of evil spirits,” from Late Latin exorcismus, from Greek exorkismos, from exorkizein “exorcize, bind by oath,” from ex “out of” (see) + horkizein “cause to swear,” from horkos “oath.” Earlier in the same sense was exorcization (late 14c.).
Online Etymology Dictionary, © 2010 Douglas Harper