encroachment
n.the act of moving into an area where you are not wanted or allowed to be. It often describes a slow, steady movement that takes over a space.
n.the gradual or systematic movement into a territory or area, often against the wishes of the existing occupants or the law. Frequently used in legal and environmental contexts to describe the expansion of urban development or the spread of invasive species.
“The city's rapid expansion caused the encroachment of buildings into the park.”
“Local residents protested the encroachment of the new highway into their private land, arguing it would destroy the local ecosystem.”
“The legal battle centered on the illegal encroachment of private interests into protected wetlands, which the government had designated as a critical habitat for endangered migratory birds.”
From encroach + -ment.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.