purification

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or an instance of cleansing or purifying.

from The Century Dictionary.

• noun The act of purifying; the act of freeing from impurities, or from whatever is heterogeneous or foreign: as, the purification of liquors or of metals.
• noun The act or process of cleansing ceremonially; a ritual observance by which the person or thing subjected to it is cleansed from a ceremonial uncleanness, as a symbol of a spiritual cleansing.
• noun A cleansing of the soul from guilt; the extinguishment of evil desire as something which does not belong to the children of God.
• noun In the Roman Catholic and Anglican churches, the pouring of wine into the chalice to rinse it after communion, the wine being then drunk by the priest.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of purifying; the act or operation of separating and removing from anything that which is impure or noxious, or heterogeneous or foreign to it.
• noun The act or operation of cleansing ceremonially, by removing any pollution or defilement.
• noun A cleansing from guilt or the pollution of sin; the extinction of sinful desires, appetites, and inclinations.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The act or process of purifying; the removal of impurities.
• noun A religious act in which a defiled person is made clean or free from sin.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the process of removing impurities (as from oil or metals or sugar etc.)
• noun the act of cleaning by getting rid of impurities
• noun a ceremonial cleansing from defilement or uncleanness by the performance of appropriate rites
• noun the act of purging of sin or guilt; moral or spiritual cleansing