circumference
noun [ C or U ] uk/səˈkʌm.fər.əns/ us/sɚˈkʌm.fɚ.əns/
圆周;周长;周线
the line surrounding a circular space, or the length of this line
the circumference of a circle 一个圆圈的周长
（圆形或弧形物体的）外周或外周长度
the outside edge of an area or object that is round or curved, or the length of this edge
the circumference of an orange 一只橙子的外周