entrench >> /ɪnˈtrɛn(t)ʃ/
Definition: [verb] Establish (an attitude, habit, or belief) so firmly that change is very difficult or unlikely.
Example: ageism is entrenched in our society
Definition: [verb] Establish (a military force, camp, etc.) in trenches or other fortified positions.
Example: the corps was now fully entrenched on the Right Bank
Definition: [verb] Encroach or trespass on.
Example: The case is quite different from that in which an outright owner of property finds that his ownership is entrenched upon by some outside intervention in the form of taxation.