hardening hardening /ˈhɑːrdnɪŋ/

noun

1. The act of making something harder (firmer, tighter or more compact)  ( hardening )
   the act of making something harder (firmer, tighter or more compact)
   
2. The process of becoming hard or solid by cooling or drying or crystallization  ( curing , hardening , set , solidification , solidifying )
   the process of becoming hard or solid by cooling or drying or crystallization
    The hardening of concrete
   the hardening of concrete
    He tested the set of the glue
   he tested the set of the glue
   
3. Abnormal hardening or thickening of tissue  ( hardening )
   abnormal hardening or thickening of tissue