to push (back) the frontiers
01
to expand the boundaries or limits of knowledge, discovery, or understanding, typically in science, technology, or exploration
例
Scientists continuously strive to push back the frontiers of medical research.
02
to extend the boundaries of a region or country, often through exploration, colonization, or territorial conquest
コロケーション
例
European explorers pushed back the frontiers of the known world by discovering new continents.
