Noun fossilisation has 2 senses

• fossilisation(n = noun.process) fossilization - the process of fossilizing a plant or animal that existed in some earlier age; the process of being turned to stone; Array
is a kind of action, activity, natural action, natural process
has particulars: petrifaction, petrification
Derived form verb fossilise₁

• fossilisation(n = noun.act) fossilization - becoming inflexible or out of date; Array
is a kind of passage, transition
Derived form verb fossilise₂