Breadcrumb Home > Dictionary > Index K keying sequence: Meaning and Definition of Find definitions for: key'ing se"quence Pronunciation: [key] — Cryptography. Cryptography. a sequence made up of letters or numbers that can encode or decode a polyalphabetic substitution cipher one letter at a time. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. keyhole saw Key Largo TrendingHere are the facts and trivia that people are buzzing about. Hanukkah Origins of the Christmas Holiday Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 Krampus: The Christmas Devil Kwanzaa ✖ Related Content Daily Word Quiz: anomie Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language