I saw that in the Holy Quran there are two forms for 'sky': Samawat السماوات and sama السَمَا. What's the difference between them?
In my earlier comments I made the following things clear:
سماوات (Samwaat) or السماوات (as-Samawaat)
Is the plural of:
سماء (Samaa') or السماء (as-Samaa')
So far so good. Then I made the following claim that needs to be verified:
Because singular is related to the sky we know, while plural refers to all the skies/heavens which Allah created. Allah explicitly quoted 7 of them.
In the qur'an the plural form was mentioned 190 times. While the singular was used 120 times.
Meanings in Arabic
First we must be aware that the term Samaa' in both its singular or plural version, refers to either mainly to the sky/heaven we know or the heavens or universe/cosmos/outer space or even clouds or rain or roof/top in almost all the cases in which it is mentioned in the qur'an. The most correct meaning can rather be deduced form the context. Not that the noun smaa' comes from the verb:
سما smaa, يسمو yasmu
Which means going upwards, climbing, raising, increasing etc. and has the corresponding noun:
Which refers, to height, highness ...
In fact if we made a check for example here, we may find that my statement about the plural is clear and can easily be confirmed. however in case of the singular the matter must be verified case by case. A much more correct statement is that it possibly refers to a different sky or heaven than that we know if the context suggest it being one of the other heavens. Maybe a hint to identify the sky we know is that it is often mentioned beside the term al-Ard "the earth" in the same verse or context (19 times in the qur'an for singular out of 191 times in which either singular or plural was mentioned beside the earth) .
Usage in the qur'an
If further we get granular with the term, we could make many distinctions between the use of these terms in the qur'an (according the following article on islamweb):
- as a top or roof or ceiling (of a building for example) as it is stated in (22:15):
Whoever should think that Allah will not support [Prophet Muhammad] in this world and the Hereafter - let him extend a rope to the ceiling, then cut off [his breath], and let him see: will his effort remove that which enrages [him]?
- as the clouds in many verses such as:
And We have sent down rain from the sky in a measured amount and settled it in the earth. And indeed, We are Able to take it away. (23:18)
He created the heavens without pillars that you see and has cast into the earth firmly set mountains, lest it should shift with you, and dispersed therein from every creature. And We sent down rain from the sky and made grow therein [plants] of every noble kind. (31:10)
- as the rain in:
And O my people, ask forgiveness of your Lord and then repent to Him. He will send [rain from] the sky upon you in showers and increase you in strength [added] to your strength. And do not turn away, [being] criminals." (11:52)
Have they not seen how many generations We destroyed before them which We had established upon the earth as We have not established you? And We sent [rain from] the sky upon them in showers and made rivers flow beneath them; then We destroyed them for their sins and brought forth after them a generation of others. (6:6)
- as the sky or heaven itself (it is the most used meaning):
[He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. (2:22)
- as the heavens of Jannah and Jahannam in the following two verses:
[They will be] abiding therein as long as the heavens and the earth endure, except what your Lord should will. Indeed, your Lord is an effecter of what He intends.(11:107)
And as for those who were [destined to be] prosperous, they will be in Paradise, abiding therein as long as the heavens and the earth endure, except what your Lord should will - a bestowal uninterrupted. (11:108)
One could even be more granular and find out that the term samaa' was used in contexts that:
- describe building,
- going upwards and climbing,
- express the ultimate top,
- refer to clouds,
- as a source of living and rizq,
- as rain,
- as what we call the troposphere,
- as a reference to the solar system,
- as different layers within the troposphere,
- expressed with more than one meaning,
- as the roof or ceiling of a house,
- as the sky/heaven in a general meaning,
- as something that has doors.
See also this article.