homeland security

剑桥词典

[ 不可数或单数名词：没有复数形式的名词 ]
activities and organizations whose purpose is to protect the US from attacks within the country by terrorists
（美国）国土安全（活动或机构）
 Homeland Security

the department of the US government that deals with homeland security
（美国）国土安全部 返回 homeland security