Pretty good observation. If God said "sphere" to humans before geometry was invented, how do you think the humans would have taken it? So of course it is stated that the earth is a "circle," and even after that statement non-believers assumed the earth was flat. What if God told you that the earth was "[i]ADpflenxor[/i]?" You wouldn't understand the statement at all. Are you under the assumption that mankind knew every descriptive term back then? Everyone was already in a state of remaining primitive.