"sacrament of the Lord's Supper, the Communion," mid-14c., from Old French eucariste, from Late Latin eucharistia, from Greek eukharistia "thanksgiving, gratitude," later "the Lord's Supper," from eukharistos "grateful," from eu "well" (see eu-) + stem of kharizesthai "show favor," from kharis "favor, grace," from PIE root *gher- (2) "to like, want." Eukharisteo is the usual verb for "to thank, to be thankful" in the Septuagint and Greek New Testament. Related: Eucharistic.
Old English halig "holy, consecrated, sacred; godly; ecclesiastical," from Proto-Germanic *hailaga- (source also of Old Norse heilagr, Danish hellig, Old Frisian helich "holy," Old Saxon helag, Middle Dutch helich, Old High German heilag, German heilig, Gothic hailags "holy"), from PIE *kailo- "whole, uninjured" (see health). Adopted at conversion for Latin sanctus.
Primary (pre-Christian) meaning is not possible to determine, but probably it was "that must be preserved whole or intact, that cannot be transgressed or violated," and connected with Old English hal (see health) and Old High German heil "health, happiness, good luck" (source of the German salutation Heil). Holy water was in Old English.
Holy has been used as an intensifying word from 1837; in expletives since 1880s (such as holy smoke, 1883, holy mackerel, 1876, holy cow, 1914, holy moly etc.), most of them euphemisms for holy Christ or holy Moses. Holy Ghost was in Old English (in Middle English often written as one word). Holy League is used of various European alliances; the Holy Alliance was that formed personally by the sovereigns of Russia, Austria, and Prussia in 1815; it ended in 1830.
late 14c., consecracioun, "the act of separating from a common to a sacred use, ritual dedication to God," especially the ritual consecration of the bread and wine of the Eucharist, from Latin consecrationem (nominative consecratio), noun of action from past-participle stem of consecrare "to make holy, devote," from assimilated form of com "with, together" (see con-) + sacrare "to make or declare sacred" (see sacred). Old English used eallhalgung as a loan-translation of Latin consecratio.
"doctrine that the body and blood of Christ coeist in and with the elements of the Eucharist," 1590s, from Church Latin consubstantionem (nominative consubstantio), noun of action from past participle stem of consubstantiare, from assimilated form of com "with, together" (see con-) + substantia "being, essence, material" (see substance). Opposed to the Catholic doctrine of transubstantiation. Related: Consubstantiate.
The term consubstantiation was employed in the doctrinal controversies of the Reformation by non-Lutheran writers, to designate the Lutheran view of the Saviour's presence in the Holy Supper. The Lutheran Church, however, has never used or accepted this term to express her view, but has always and repeatedly rejected it, and the meaning it conveys, in her official declarations. [Century Dictionary]
"act or fact of being made holy," 1520s, from Church Latin sanctificationem, noun of action from past-participle stem of Late Latin sanctificare "to make holy," from sanctus "holy" (see saint (n.)).