◎ 弦切角 xiánqiējiǎo[angle of osculation] 圆的切线和过切点的弦所成的角-----------------国语辞典：圆的切线与过切点的任何弦所构成的角。英语 chord angle (i.e. angle a chord of a curve makes to the tangent)
◎ 弦歌 xiángē[sing to the accompaniment of stringed instruments] 用琴瑟等伴奏歌唱-----------------国语辞典：依和著琴瑟的声音来咏诗。《淮南子．俶真》：「弦歌鼓舞，缘饰诗书，以买名誉于天下。」《史记．卷四七．孔子世家》：「三百五篇孔子皆弦歌之，以求合韶武雅颂之音。」孔子到鲁国武城听到子游用弦歌之声教化人民。典出《论语．阳货》。比喻以礼乐教化群 众。唐．刘禹锡〈国学新修五经壁本记〉：「俾我学徒，弦歌以时。」英语 to sing to a string accompaniment, education (a reference to teaching the people Confucian values by means of song in ancient times)