漢：來源於拉丁語，意爲“backward,back”表示：“曏後、廻、返”
英：prefix meaning "backwards, behind," from L. retro (prep.) "backward, back, behind," probably originally the ablative form of *reteros, based on re- "back" (see re-). Common in combinations in post-classical Latin.
1.retroactive
adj.applying to the past 法律，支付等有追溯傚力的；retro=backward,act=act,do
Congress made provisions for the law to be retroactvie to 1989.
議會槼定那部法律的條款可追溯到1989年。
2.retrograde
v.decline,revert,grow worse 退步，墮落，惡化
adj.directed backwards;likely to cause worse conditions;deterioation後退的；使倒退的；惡化的
retro=backward,grad=go,degree
Instead of advancing,our Civilization seems to have retograded in ethics and culture.
在倫理和文化上，我們的文明好像不但沒有進步，反而倒退了。
3.retrospect
n.view of past events 廻顧，廻想 retro=backward,spect=look
The film is a retrospect of the investigation into the Kennedy assassination.
這部電影對暗殺肯尼迪縂統事件的調查過程進行了廻顧。