לוּ (lû) is
a Hebrew interjection
meaning if. It appears
25 times
in 12 books of the Hebrew Bible
(Strong's H3863).
Same Hebrew root (TWOT 1085)
Range of meaning (TWOT 1085)O that; If only …!, O that!, would that!; if; peradventure, I pray thee, though, I would, would God
Full entry: Brown-Driver-Briggs and Strong's
לוּconjunction: O that
1.if
2.If only …! i.e. O that! would that!
Strong's H3863לוּא: a conditional particle; if; by implication (interj. as a wish) would that! KJV:if (haply), peradventure, I pray thee, though, I would, would God (that).
Meanings: Brown-Driver-Briggs (1906) and Strong's Hebrew Dictionary (1890), public domain, via the Open Scriptures Hebrew Bible Project (CC BY 4.0). TWOT numbers for reference only.