Stedfastness sted'-fast-nes:
(1) stereoma, "firmness": "The steadfastness of your faith in Christ" (Colossians 2:5). Some take this figuratively, in a military sense, of a "solid front" (see Thayer, Greek-English Lexicon of New Testament, under the word).
(2) sterigmos, "stability" (2 Peter 3:17; compare 1 Corinthians 15:58).