OBSabbr.观察(=Observation)abbr.瞭望台(=Observatory)abbr.已废的(=Obsolete)abbr.无线电定向标选择器(=Omnibearing Selector)
observing time观测时间
observing tube观察筒
observing data监测数据
obstetric hook产科钩
obstetric canal产道
obstetric scoop产勺
obstetric chair妇科用椅,分娩椅,产科椅
obstacld degree障碍度
obstetric table产床
obsequent river逆向河