to harden the surface of (steel or iron) by the addition of carbon at high temperature
face-harden in American English
(ˈfeɪsˌhɑrdən)
verb transitive
caseharden (sense 1)
face-harden in American English
(ˈfeisˌhɑːrdn)
transitive verb
to harden the surface of (metal), as by chilling or casehardening
Word origin
[1895–1900]This word is first recorded in the period 1895–1900. Other words that entered Englishat around the same time include: Marxism, apothecaries' measure, calling card, freewheel, neon