🔼The name Bel in the Bible
Bel is the name of the patron deity of Babylon. According to The Oxford Companion To The Bible, Bel is another name of Marduk . Marduk is mentioned only once in the Bible, by the prophet Jeremiah (50:2). Bel gets a little more Biblical screen time, both from Jeremiah (50:2, 51:44) and Isaiah (46:1). The Septuagint features three apocryphal additions to the Book of Daniel, one of which is a two-parter titled Bel and the Dragon. In the Bel story, Daniel insists that food offered to Bel isn't eaten by Bel, and sets out to reveal the identity of the midnight snacker: Bel's priests, who are subsequently executed.
🔼Etymology of the name Bel
It's now commonly believed that there was no actual person behind these gods, so it's without merit to say that Bel and Baal are the same. Obviously, a collective or focused religious reverence of the Babylonian culture is not the same as that of the Canaan culture, and their manifestations (namely Bel and Baal) are also not the same. And that these cultures called their gods Lord is also not so unthinkable, as modern believers do the same thing.
It may also be that the Bel worshipers called their deity Lord, but that the authors of the final version of our Bible (who lived in Babel and competed with the Bel cult), transliterated this name deliberately into בל (Bel), so that it strongly resembled the adverb בל (bal), which is a particle of negation meaning "not". It comes from the root בלה (bala), meaning to be old or worn out:
Bel sounds as much like Lord as it does like Nope!.