A Short Note on Qaf

Qaf occurs in S 42:2 Ayin sin qaf.

See: The Perspicuity of the Quran and It’s Mysterious Letters

and S 50:1 Qaf. By the glorious Quran.

From Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs:

And from his narration on the authority of Ibn 'Abbas that he said in the interpretation of Allah's saying (Qaf.): '(Qaf.) He says: it is an azure mountain overlooking this world, and the colour of the sky takes from it; Allah swore by it, (By the glorious Qur'an) and He swore by the glorious, noble Qur'an, Altafsir.com -تفسير ايآت القرآن الكريم (73-0-1-50)

From Chagigah 12a:7

It was taught in the Tosefta: Tohu is a green line that encompasses the entire world, and from which darkness emerges, as it is stated: “He made darkness His hiding place round about Him” (Psalms 18:12), indicating that a line of darkness surrounds the world. Vohu; these are damp stones submerged in the depths, from which water emerges, as it is stated: “And He shall stretch over it the line of tohu and stones of vohu” (Isaiah 34:11), which demonstrates that tohu is a line and that vohu is referring to stones. Chagigah 12a:7

The Original Sources of the Qur'an [Chapter III]

Qav in Hebrew means 'line'.