by and by—soon; before long:
- They could see the smoke, and by and by a shell would explode in their midst.
by the by —(introductory or parenthetical) in passing; incidentally (also: by the way):
- By-the-by, Martin—any message from my lady mother?
by and by—soon; before long:
by the by —(introductory or parenthetical) in passing; incidentally (also: by the way):