In the Hebrew Bible. Day meant a literal day.
Not according to Jewish or Catholic or Eastern Orthodox interpretation, not just modern, but going back centuries to at least Augustine, or probably even Hillel (a Jewish person more familiar with should comment on this).
This notion of interpreting Genesis literally is really a late-modern era fundamentalist Protestant position unsupported by historical principles of exegesis.
When I hear fudamentalists refer to themseleves as "Bible-believing", I have to laugh. You can't believe what you don't understand.