"The words in the Old Testament have the meaning of 6, 7 or 8."

The days in the Genesis creation myth are defined as a morning and evening which constitutes a day; it didn't take the earth a billion years to rotate. The ages of the patriarchs are counted off in years; if those "years" meant eons, the stated ages would be that much further from real possibility by magnitudes. It takes desperately wishful thinking to make Genesis a literal historical account in the language of any period of history.