Rāqīaʿ derives from the root rqʿ ( רָקַע‎), meaning 'to beat or spread out thinly'. These words all translate the Biblical Hebrew word rāqīaʿ ( רָקִ֫יעַ‎), used for example in Genesis 1.6, where it is contrasted with shamayim ( שָׁמַיִם‎), translated as ' heaven(s)' in Genesis 1.1. This in turn is a calque of the Greek στερέωμᾰ ( steréōma), also meaning a solid or firm structure (Greek στερεός = rigid), which appears in the Septuagint, the Greek translation made by Jewish scholars around 200 BCE. The same word is found in French and German Bible translations, all from Latin firmamentum (a firm object), used in the Vulgate (4th century). It later appeared in the King James Bible. In English, the word 'firmament' is recorded as early as 1250, in the Middle English Story of Genesis and Exodus. Today it survives as a synonym for 'heaven'. The word is found in the King James Version, Tyndale, Douay-Rheims, and other early English translations of the Bible.

In biblical cosmology, the firmament is a vast solid dome, created by God on the second day of creation, which divides the primal “waters” into upper and lower portions. The sun, planets and angels and the firmament.

The firmament, Sheol and tehom are depicted. For the video game, see Firmament (video game).

Biblical flat earth theory