sector
n
1 part of a circle lying between two straight lines drawn from the centre to the circumference 扇形. => illus at circle 見 circle 插圖.
2 part or branch of a particular area of activity, esp of a country's economy (活動領域的)部門; (尤指)經濟領域
the manu`facturing sector, ie all the manufacturing industries of a country 制造業
the `service sector, eg hotels, restaurants, etc 服務性行業.
3 any of the parts of a battle area, or of an area under military control 戰區; 防區
an enemy attack in the southern sector 敵軍對南部戰區的進攻.