NRWiktionary 原文英美abbr.天然橡胶（Natural Rubber）；水平调节控制中文释义来自 ECDICT释义形容词adjective1(finance, entertainment) Initialism of not rated.名词noun1(sports) Initialism of national record.专有名词proper noun1(rail transport) Initialism of Network Rail, a rail infrastructure manager in Great Britain.