fos‧sil‧ize also fossilise British English
1 [usually passive]
if people, ideas, systems etc fossilize or are fossilized, they never change or develop, even when there are good reasons why they should change:
Most couples, however fossilized their relationship, have some interests in common.
2 [intransitive and transitive]HEG
to become or form a fossil by being preserved in rock:
fossilized dinosaur bones
—fossilization noun [uncountable]