noun
reply letter; written reply
A letter written in response to a received letter; somewhat formal or literary.
先日のお手紙に対する復文をしたためました。
I have written a reply to your recent letter.
noun, noun or participle which takes 'suru'
retranslation; back-translation
Translating a text back into its original language, often as an exercise or to check accuracy. Can be used as a suru-verb.
翻訳の授業で英文を日本語に訳し、さらに復文する練習をした。
In translation class, we practiced translating English into Japanese and then retranslating it back into English.