Bible dictionaries
By and by
What Bible dictionaries say about “By and by”, one article after the other.
Easton’s Bible Dictionary & Webster’s 1828 Dictionary
By and by - (Easton's Bible Dictionary)
Immediately (Matt. 13:21; R.V., "straightway;" Luke 21:9).
Matthew George Easton, Easton’s Bible Dictionary; Noah Webster, American Dictionary of the English Language (1828)
The article in Easton + Webster 1828International Standard Bible Encyclopedia (ISBE 1915)
In the sense of "immediately" is the King James Version translation of exautes, of Mr 6:25 (the American Standard Revised Version "forthwith"); of euthus, Mt 13:21 (the American Standard Revised Version "straightway"); of eutheos, Lu 17:7 (the American Standard Revised Version "straightway"); Lu 21:9 (the American Standard Revised Version "immediately"). In English literally this meaning is obsolete (compare: "After you have dyned and supte, laboure not by and by after, but make a pause--the space of an howre or more with some pastyme") (Babees Book, EETS, 247).
International Standard Bible Encyclopedia — James Orr, general editor and contributors; CrossWire SWORD module ISBE 2.2
The article in ISBE 1915