1Harden the surface of (a material)‘the blades are case-hardened with reinforced backing plates’
- 1.1 Give a hard surface to (iron or steel) by carburizing it.‘the grade of steel was unsuitable for the type of heat treatment process used to case-harden the gears’
- 1.2 Make (someone) callous or tough.‘years of surgical experience did not case-harden him to suffering’
- 1.1 Give a hard surface to (iron or steel) by carburizing it.
We take a look at several popular, though confusing, punctuation marks.