perimeter
UK: pəˈrɪmɪtə | US: pəˈrɪmɪtər
n. the continuous line forming the boundary of a closed geometric figure
n. the outer limits or edge of an area or object
n. (military) a fortified boundary or defensive line
The word "perimeter" originates from Greek, combining "peri-" (meaning "around") and "-meter" (derived from "metron," meaning "measure"). It entered English via Latin and Old French, retaining its core idea of measuring the boundary or outer edge of a space. The morphemes logically reconstruct the original spelling and meaning: "peri" (encircling) + "meter" (measuring) = "measuring around."
The perimeter of the rectangle is calculated by adding all four sides.
Security guards patrol the perimeter of the building at night.
The garden’s perimeter was marked by a low stone wall.
The military established a secure perimeter around the camp.
She walked the entire perimeter of the park every morning.