Why is "omnipotent" stressed iambically?

Solution 1:

It is very frequent, at least in BrE, that long Latin/Greek words are stressed on the third-last syllable. In phonetics there are special terms for the syllables.

the ultimate syllable is the last one

the penultimate is the second-last one

the propenultimate is the third last one.

These terms are very academic and not appropriate for quick notation. (In my notes I write: stress on 3m meaning on syllable 3 minus, the third-last one.)

I'll try to find sth on the Internet about words with stress on the third-last one and whether one can formulate a general rule.

After looking around a bit I have the feeling such an article has to be written yet.

Solution 2:

The "present" in "omnipresent" is easily recognizable from the interpretation as being from the independent word "present", so it tends to have the same pronunciation as that independent word. Compare "equidistant", where the "distant" portion would always be stressed like the independent word "distant".

Is the "potent" in "omnipotent" recognizable as being the independent word "potent"? Not so much, since "potent" is uncommon, and now has a sexual connotation missing from "omnipotent". So the pronunciation of the word "potent" is not so likely to influence the pronunciation of the last part of "omnipotent". (Nonetheless, pronouncing the last part of "omnipotent" just like the word "potent" is an option, for me.)

Solution 3:

The Latin prefix 'omni-' is not commonly used by itself as a stand-alone word. Prefixes often alter the syllabic stress of a word, so let's not be too surprised that the power of 'potent' is changed by such a meaningful prefix. Do I get an extra point for punning?