by the by
Definition from Wiktionary, the free dictionary
- (idiomatic) used to introduce a new topic; incidentally
1990, Susan Sherman, The color of the heart: writing from struggle & change, 1959-1990:
- These sudden rains. Not tropical - with lightning, thunder, great release after hours of tension. But more nonchalant, more "by-the-by." As if the clouds, rushing to get somewhere else, were to drop some rain in passing.
by the way