[a. Fr. frettage, f. fretter to ring, f. frette FRET sb.5] a. The process of shrinking on rings of metal about the breech of a gun to give additional strength. b. The collection of rings thus employed.
1882. Rep. Chief of Ordnance, 244 (Cent. Dict.). The gun, one it has been tubed, ordinarily receives an exterior frettage.