Man. Kind of hostile, PaulK. I wasn't attacking you, or anyone in particular, just a general trend on this topic. But I'll go through your rebuttals one at a time. (I don't know how to do the snazzy colored quote-boxes, so I'm just going to rely on old-fashioned quotation marks)
You said: "Firstly if you want precision remember that we are dealing with Hebrew and not English. And every source I've checked indicates that the Hebrew word ("chuwg") indicates a circle, not a sphere."
Saying we're dealing with Hebrew, and that "chuwg" indicates a circle is irrelevant. I never even insinuated that 'circle' and 'sphere' are interchangeable, nor would I say that 'chuwg' means 'sphere.' The two words have fundamentally different meanings. My point was that 'circle' and 'sphere' can sometimes function as basic synonyms. A synonym is not necessarily a word that means the exact same thing. It is a word that has nearly the same meaning, or that serves as a figurative or symbolic substitute.
You said: "Secondly the Earth is an oblate spheroid (and I did NOT need to look that up) rather than a perfect sphere - but that doesn't mean that "sphere" is not an adequate description in circumstances where that level of precision is not required. And "sphere" is still far more accurate than "circle"."
I didn't mean to imply that /everyone/ would have to look it up. In fact, having seen some of the intelligent discussions on these boards, I'm certain there are plenty of people who have more scientific experience than I do. But either way, we're in agreement. Your second rebuttal is exactly my point. Sphere is completely adequate in circumstances where further precision is not required, though 'oblate spheroid' is far more accurate than 'sphere.' I analogize this to 'circle' and 'sphere.' 'Sphere' is far more accurate than 'circle,' I agree. However, that does not necessarily mean that 'circle' is not an adequate description in circumstances where that level of precision is not required.
Tying together this with your third point, the context/importance of the term, as well as their vast audience, are essential. Think about how you would explain something to a large group of people with very diverse backgrounds, ages, and educational levels. If everyone I am speaking to is educated, I'll probably be as specific and precise as I can be. If there are many people with less education, I'll be less specific and precise; the more educated individuals will be able to add the specificity and figure out what I meant, but everyone will be able to understand me.
Let me apply that analogy to this example. If I'm teaching a room of physics students, and one of them asks me what shape the Earth is, I'm going to reply "oblate spheroid," or "nearly an ellipsoid." If my reference to the Earth's shape is in passing conversation, or in response to a question posed by a random group of teenagers, I'm likely to reply more simply "sphere," even if some physics students are in the room; the physics students can pull me aside afterwards and ask me to elaborate, or they'll know what I meant. Finally, if I'm talking to a two-year-old about shapes, and she says 'The earth is a square!', I'll probably correct her by saying 'No, honey, it's a circle.' And I doubt anyone in the room would stand up and correct me on it; they would know what I meant.
Further, the Bible is not intended to be, nor should it be, a science textbook. The use of the word 'chuwg' is in passing. A random book or warning on a hairdryer may mention that water conducts electricity, again in passing, because it does not want to go into a science-text-book length discussion about the fact that absolutely pure water does not conduct electricity very well at all, but the electrolytes dissolved in water do. Higher specificity is not always required, or even desired.
You said: "Finally let us be clear about dictionary.com. It lists several SETS of definitions. The fourth entry of ONE set includes "sphere". None of the rest do (and we have NO examples of that usage other than the very verse in question - where such a reading is incorrect)."
Again, this is exactly my point. Generally, circle does /not/ mean sphere. However, it is sometimes used synonymously - hence my pointing to one definition in a dictionary, and a listing of 'sphere' under 'circle' in the thesaurus.