Kai (conjunction)

Kai (και "and"; Modern Greek[ce]; Ancient Greek[kai]; sometimes abbreviated k) is a conjunction in Greek, Coptic (ⲕⲁⲓ) and Esperanto (kaj; IPA: [kai̯]).

Kai is the most frequent word in any Greek text and thus used by statisticians to assess authorship of ancient manuscripts based on the number of times it is used.


Because of its frequent occurrence, kai is sometimes abbreviated in Greek manuscripts, by a ligature (comparable to Latin &), written as ϗ (uppercase variant Ϗ; Coptic variant ), formed from kappa (κ) with an extra lower stroke. It may occur with the varia above it: ϗ̀.

Authorship of ancient textsEdit

The number of common words which express a general relation ("and", "in", "but", "I", "to be") is random with the same distribution at least among the same genre. By contrast, the occurrence of the definite article "the" cannot be modeled by simple probabilistic laws because the number of nouns with definite article depends on the subject matter.

Table 1 has data about the epistles of Saint Paul. (Abbreviations: Rom Romans; Co1 1st Corinthians; Co2 2nd Corinthians; Gal Galatians; Phi Philippians; Col Colossians; Th1 1st Thessalonians; Ti1 1st Timothy; Ti2 2nd Timothy; Heb Hebrews). 2nd Thessalonians, Titus, and Philemon were excluded because they were too short to give reliable samples. From an analysis of these and other data [Mor65, p. 224] the first 4 epistles (Romans, 1 Corinthians, 2 Corinthians, and Galatians) form a consistent group, and all the other epistles lie more than 2 standard deviations from the mean of this group (using   statistics).

Table 1: Number of sentences in Paul's Epistles with 0, 1, 2, and ≥3 occurrences of kai
Rom Co1 Co2 Gal Phi Col Th1 Ti1 Ti2 Heb
None 386 424 192 128 42 23 34 49 45 155
One 141 152 86 48 29 32 23 38 28 94
Two 34 35 28 5 19 17 8 9 11 37
Three or more 17 16 13 6 12 9 16 10 4 24


This article incorporates material from Econ 7800 class notes by Hans G. Ehrbar, which is licensed under GFDL.

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