How to say "perimeter" in Japanese

• 外周がいしゅうCommon
  nounCovers the perimeter of an area, building, plot of land, or figure: the outer boundary itself and the length around it. This is the word for the measurable edge of a site or shape.
• 外回りそとまわりCommon
  nounViews the perimeter as the outside of a loop or circuit: on a ring road it names the outer direction of travel. For the boundary of a plot, building, or figure, use 外周.

Use 外周 for the perimeter of a shape, plot, or building — the outer boundary itself and its length; 「外回り」 covers the outside of a loop or circuit, such as the outer direction on a ring road.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 外周がいしゅうouter circumference
• 外回りそとまわりcircumference
• 周長しゅうちょうperimeter
• 周囲長しゅういちょうperimeter
• 周しゅうperimeter
• 全周ぜんしゅうwhole circumference