Canon: The Meaning of the Latin Term
This article serves as an stand-alone introduction to the book, The Roman Canon: An Interlinear Translation, compiled by Craig Toth.
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Most of us know what the Canon Missæ, the Roman Canon of the Mass, is, but if asked what the word canon actually means in this context, we might find ourselves at a loss, in possession of misleading information, or in doubt of a sound answer. After all, in addition to “Canon of the Mass”—what the ancient Gelasian Sacramentary calls the canon actionis, i.e., the canon of the sacred activity of the Sacrifice—we find, to name but a few, the following expressions: the canon of scripture, the Buddhist Canon (viz., the Tripiṭaka), a canon of a cathedral chapter, the canons of the Council of Trent, ecclesiastical canons, the Western canon, the Shakespearean canon, the canon type-size, the canon of the saints, the canons of statutory construction, the Canon of Polykleitos (both his treatise on the proportioning of the human figure and the celebrated statue), the canons of criticism, the canons of taste, and rather famously Johann Pachelbel’s Canon in D. Even in this incomplete inventory, canon patently exhibits several, albeit akin, ecclesiastical and secular senses: a standard of judgment or of excellence or of conduct, a precept, an authoritative or sanctioned list, an established norm, a model, a criterion par excellence against which something is measured, a yardstick, a touchstone, a basic governing principle, a body of general principles, a decree, an edict, a law, a regulation, an ordinance: In sum, a rule in virtually every sense, the Latin regula.
The word’s earliest history tracks its multiple significations, too. As a learned borrowing, canon entered the English lexis, in part via Old French, from the Latin canōn, itself a loan-word. The Romans appropriated it from the Greek κᾰνών (kanṓn), meaning, according to the Liddell-Scott lexicon, “straight rod, bar, staves [strengthening rods across the inside of a shield], a weaver’s rod [loom-rod], a ruddled line [red-ochre-saturated snap-line] used by masons or carpenters, straight edge, rule [straight-rule for drawing geometric figures], ruler, beam of a balance, curtain rod, the monochord [acousticians’ single-string instrument], model, standard, severe critic, general rule, table of dates, system of chronology, astrological table, limit, boundary, sphere of action, assessment for taxation, tariff.” In addition to denoting a measuring line, ruler, and model, the Latin borrowing also denominated the sound-board of a hydraulus or water-organ (Lewis-Short, Glare dictionaries). According to Souter’s glossary, canōn in Later Latin had amassed the following constellation of definitions:
grammatical rule; metrical scheme or type; annual payment (tax, tribute) to Rome from the provinces; any payment (public or private); table [orderly display of data], list (of biblical books, etc., esp. such as are appointed to be read in the public services of the Church); rule (statute, canon) of the Christian life (esp. such as are settled by a church synod or council as binding, particularly on the secular clergy, or (later) on monks); the canon of the Mass (part of the official liturgy of the Roman Church (GREG M. epist. 14.2.9, 26).
In order to puzzle out the precise signification of canon in the Roman Missal’s name Canon Missæ, it will be helpful to interrogate first what the word means in other expressions. The canon of scripture is the collection of biblical books admitted by rule as fulfilling the criterion of divinely inspired literature. The Shakespearean canon comprises the plays and poems conclusively assigned by sober scholarly consensus to the Bard, which conform to critical standards of authenticity. A literary canon is a traditional collection of writings, against which other writings are evaluated. A canon of a cathedral identifies a clergyman who lives a religious life comporting with an approved ecclesiastical rule and discipline, i.e., he lives a vita canonica. Canons of artistic style and taste embrace formalized criteria, a body of principles, a touchstone or standard of discrimination whereby we judge the becomingness, concinnity, and beauty of an object of aesthetic perception. Ecclesiastical canons comprehend the authoritative laws, definitions, decrees, codes, and rules pertaining to Christian life. The canon of the saints denotes the catalogue of the servants of God whose pattern of heroic sanctity the Church has definitively ratified and acknowledged.
In light of this brief digest of sundry meanings of canon, how might we explain the word as applied to the great Eucharistic Prayer of the Latin rite, the actio sacrificii? Happily, we need not overtax our ingenuity at the risk of being too clever by half. Almost 1,200 years ago, the Benedictine abbot Walafrid Strabo (c. 808-49), in his Book on the Beginnings and Developments of Certain Matters in Ecclesiastical Observances, “the first handbook of liturgical history,” answered the question decidedly for us all:
The actio is called the Canon because it is the legally prescribed and rule-conforming confection of the sacraments.
 Etymologists propose that Greek κᾰνών is related to the word for reed found in Ancient Near Eastern languages (probably the genus Arundo or Phragmites): Sumerian GI.NE (Sumerogram 𒄀, GI, “reed”), Akkadian (Old Babylonian), qanûm (syllabic 𒂵𒉡𒌑𒌝), “reed, measuring reed, unit of length”; later dialectal form qanû, 𒂵𒉡𒌑), and Hebrew, qāneh (קָנֶה), from which comes the Ancient Greek κᾰ́ννᾱ (kánnā), “giant reed” (Arundo donax), and ultimately the English word cane. The latter word derives from canna, the Latin transliteration of the Greek, by way of Old Provençal, Old French, and Anglo-French. In Hebrew, as in related words in other languages of the Near East, qāneh additionally meant a measuring-rod, a unit of measure, beam of scales, shaft of a light stand (Brown-Driver-Briggs lexicon).
 Canon… actio nominatur… quia ea est legitima et regularis sacramentorum confectio (c. 22, of the Libellus de exordiis et incrementis quarundarum in observationibus ecclesiasticis rerum.