Genesis 1:6-8 New Revised Standard Version (NRSV)
6 And God said, “Let there be a dome in the midst of the waters, and let it separate the waters from the waters.” 7 So God made the dome and separated the waters that were under the dome from the waters that were above the dome. And it was so. 8 God called the dome Sky. And there was evening and there was morning, the second day.