by the byspokenMENTION used when mentioning something that may be interesting but is not particularly important 顺便说一下 By the by, Ian said he might call round tonight. 顺便告诉你,伊恩说他也许今天晚上会过来。
→ by the way at way1by the by• By the by, John might come over tonight.• But that's by the by.
→ by the by at by1(3)