top-down（adj.） 英 [ˌtɒp ˈdaʊn] 美 [ˌtɑːp ˈdaʊn] by 1964 in computer programming; by 1969 as "authoritarian, hierarchical;" see top (n.1) + down (adv.), as though "from the top downward, down from on high."该词起源时间：1964年
