By the bye Meaning, Definition & Usage

  1. adverb introducing a different topic; in point of fact
    incidentally; by the way; apropos.
    • incidentally, I won't go to the party

WordNet


Definitions
  1. . See under Bye.
Definitions
  1. in passing; by way of digression; apropos to the matter in hand. Written also by the by.

Webster 1913