Inured; toughened. / Unfeeling; pitiless; callous. / Firmly established or unlikely to change; inveterate. / (computing, military) Having extra defences against attack; highly fortified.

One who, or that which, hardens. / A chemical substance added to something in order to harden it; used especially with paints, varnishes and resins.

plural of hardener

Third-person singular simple present indicative form of harden

(intransitive) To become hard (tough, resistant to pressure). / (transitive, ergative) To make something hard or harder (tough, resistant to pressure). / (transitive, figuratively) To strengthen.

(metallurgy) The repeated plastic deformation of a material, causing a permanent distortion of its crystal structure, and an increase in its strength

Alternative spelling of case hardening

present participle of case harden

(metallurgy) The process of imparting greater hardness to the surface of a piece of metal.

(physics, chemistry) The protection of semiconductor devices from the effects of ionizing radiation.