Usage note
回信是指回复别人写给你的信件。比如,当你收到朋友的来信时,你可以通过回信来表达感谢或分享自己的想法。
huíxìn shì zhǐ fùhui běn rén xiě gěi nǐ de xìnjiè. rúguǒ, nándāng nǐ shōudào péngyǒu de láixìn shí, nǐ kěyǐ tōuguò huíxìn lái biǎo达表达 gǎnxì huò xiǎnɡfānɡ zēnɡ jīnɡ.
回信 means replying to letters from others. For example, when you receive a letter from a friend, you can reply to express gratitude or share your thoughts.