- 2Signification: positionboundary extremity frontier confine limitend outpost periphery border
- 3Signification: borderboundary limit hinterland outskirts frontier
- 4Signification: new field of learningcutting edge breakthrough frontier
- 5Signification: perimeteredge borderline borderperiphery frontier fringe
- 6Signification: limitborder limitation confine boundend extent frontier boundary