There are four Hebrew words thus rendered in the Old Testament which we may briefly notice.

Raki’a, Authorized Version, firmament. [Firmament] Shamayim . This is the word used in the expression “the heaven and the earth,” or “the upper and lower regions.” (Genesis 1:1) Marom, used for heaven in (Psalms 18:16; Isaiah 24:18; Jeremiah 25:30). Properly speaking it means a mountain as in (Psalms 102:19; Ezekiel 17:23) Shechakim, “expanses,” with reference to the extent of heaven. (33:26; Job 35:5) St. Paul’s expression “third heaven,” (2 Corinthians 12:2) had led to much conjecture. Grotius said that the Jews divided the heaven into three parts, viz., The air or atmosphere, where clouds gather; The firmament, in which the sun, moon and stars are fixed; The upper heaven, the abode of God and his angels, the invisible realm of holiness and happiness the home of the children of God.