Lexical Definition

‎χξϛ‎ chx stigma (khee xee stig'-ma) 666 ^G:A
the 22nd, 14th and an obsolete letter (‎στίγμα‎ as a cross) of the Greek alphabet (intermediate between the 5th and 6th), used as numbers; denoting respectively 600, 60 and 6

six hundred threescore and six.

• 666 as a numeral

Abbott-Smith

χξϛʹ (on ς, v.s. Ζ), in T, Tr., Rec. for ἑξακόσιοι ἑξήκοντα ἕξ,
six hundred and sixty-six (L, mg., R, mg., six hundred and sixteen), the mystical number of the Beast: Re 13:18 (on the interpretation, v. Swete, Ap., 172 f.).†

Abbott-Smith References