1. (p. pr. & vb. n.) of Harden.

2. (n.) Making hard or harder.

3. (n.) That which hardens, as a material used for converting the surface of iron into steel.

abidingness acclimation acclimatization accommodation accustoming adaption adjustment agglutination arteriosclerosis atherosclerosis breaking breaking-in calcification callusing case hardening changelessness clumping clustering compression concentration concretion condensation conditioning consolidation constancy cornification crystallization densification domestication durability durableness duration endurance familiarization firming firmness fixedness fortification fossilization frozenness granulation habituation hornification housebreaking immobility immovability immovableness immutability induration indurative inurement invariability invariableness inveteracy invigoration lapidification lastingness lithification long standing naturalization orientation ossification permanence permanency perpetualness persistence persistency petrifaction petrifactive petrification petrifying quiescence refreshment reinforcement reinvigoration restrengthening revivification rigidity sclerosis seasoning setting solidification solidity stability standing stasis steadfastness steeling stiffening strengthening taming tempering torpor toughening training unchangeability unchangingness vitrifaction vitrification