Is the hijab considered a covering for the hair based on linguistic proof, especially since the Noble Qur'anic verse did not explicitly mention hair?

A woman's hair is considered 'awrah (private parts) and must be covered. It is impermissible to expose it to non-mahram (definition) men, by consensus of the scholars. The proof for this is Allah's saying: "And let them draw their headcovers over their bosoms" (Quran 24:31). 'Khumur' (headcovers) are what a woman uses to cover her head. And Allah's saying: "They should draw over themselves some of their outer garments" (Quran 33:59). Some scholars have even gone to the extent of prohibiting looking at a woman's hair even if it is detached from her.