With help from other Quranic verses and traditions of the imams, commentators of the Quran have presented several possible meanings for these terms. Some say the two are metaphorically referring to the same thing, which is the rank of Allah's (swt) command and governing of this world’s affairs.
1- What is meant by “kursiyy” is where Allah's (swt) knowledge has way; which is all the heavens and earth and everything in this universe.
2- The arsh and kursiyy are both ranks of dominion and command that belong to Allah (swt); the difference between the two being that the arsh is Allah's (swt) dominion regarding this material and physical universe, while the other is His dominion regarding the world of angels and souls, which is the metaphysical world.
3- The arsh is a real thing that exists in this world, and isn't a figure of speech, and the same goes for kursiyy, which encompasses all the heavens and earth.4- In some verses the arsh is metaphorical, while in other verses, it isn't and is referring to something real that exists.
In Arabic, the term “arsh” means throne. Arsh originally means anything that has a roof and its plural form is “Urush”, and the reason why the throne of kings has been named arsh is because of its highness.
The term “kursiyy” refers to the throne, knowledge, kingdom, dominion, power and wisdom of Allah (swt).
In the Quran, other than the heavens and earth and everything in between, two other things have been pointed to by the names of “kursiyy” and “arsh”.
Concerning the meaning of these two terms, Islamic scholars have presented different theories with the help of other verses and hadiths from the imams:
Some say that what might be meant by “arsh” is the throne of dominion and power, and that what might be meant by “kursiyy” is the seat of highness and rule; both phrases are figurative language and are referring to a rank in which commands are issued and all matters in this universe are governed.
The word “arsh”, meaning throne, has been mentioned in the Quran four times (Yusuf:100 and Nahl:23, 38, 42). Allah’s “arsh” has been mentioned in the Quran 21 times. These verses are important metaphorical verses of the Quran. There are different possibilities as to what might be meant by these verses:
1- What might be meant is the rank of dominion and governing of the affairs of this world, especially since “governing”, “directing” and the like have come after the term “arsh” in these verses, such as “ثم استوی علی العرش یدبر الامر...” ([Allah] settled on the Throne, directing the command…).
2- The second possibility is for “arsh” to refer to something real and specific that actually exists, not just a rank, such as the verse that says: “و هو رب العرش العظیم” (He is the Lord of the great throne). The apparent meaning of this verse is that there is something that Allah (swt) is the lord of. The verse “الذین یحملون العرش و من حوله” (Those who carry the throne and those [circulating] around it) also corroborates such a meaning.
3- The third possibility is a combination of the two previous ones and distinguishes between verses; meaning that is says that in some verses what is meant by the arsh is something that really exists while in other verses it has been used metaphorically.
In explanation of the meaning of arsh, Allamah Tabatabai states: “The arsh is a reality and something that truly exists. The verse that says “ثم استوی علی العرش” is both a figure of speech that illustrates how Allah’s (swt) governing covers everything and that everything is under His control, and is telling us of a reality which is a rank and place where the means to governing everything are gathered there. Verses 7 of surah Mu’min, 17 of surah Haqqah and 74 of surah Zumar are apparently speaking of a reality that truly exists.”
Also, what is deduced from hadiths that speak of the arsh is that it is a reality and that actually has creatures (possibly angels) carrying it. Imam Sadiq (as) was asked about the kursiyy and arsh, he responded: “ان للعرش صفات کثیرة مختلفة له فی کل سبب وضع فی القرآن صفة علی حده...” The arsh has many different attributes; in every place of the Quran that it has been mentioned, attributes of it that are in correspondence with the place it has come have also been mentioned.” For instance, in “رب العرش العظیم”, “the great throne” is referring to Allah’s (swt) great dominion. In “الرحمن علی العرش استوی”, what is meant is that Allah (swt) covers all of His dominion, meaning that He has knowledge of everything. If it ever happens that arsh and kursiyy are mentioned together, each will have its own separate meaning. That is because both the arsh and kursiyy are two of the greatest doors to the unseen and both are part of the unseen themselves, therefore from this perspective, the two are alike. The difference between the two though, is that the kursiyy is the outer door to the unseen and every new thing and all things that are created come from there, while the arsh is the inner door to the unseen, meaning that knowledge of all things and creation and the knowledge of measures and boundaries and place of all things, and also willpower, knowledge of words and movements and refrain and knowledge of the beginning of all things and their end all comes from there.
So, the arsh and kursiyy are two doors next to each other; the only thing is that the realm of the arsh differs from that of the kursiyy and that the knowledge of the first is more concealed and hidden than that of the latter…
In explanation of the phrase “ثم العرش فی الوطل متفرد من الکرسی”, Sheikh Saduq says: “The arsh comes before the kursiyy and directly has an impact on it; the arsh and kursiyy are two heavenly things…
The prophet of Islam (pbuh) has been reported saying: “ان الشمس و القمر و النجوم خلقن من نور العرش” (The sun, moon and stars have all been created from the light of the throne of the lord).
The meaning of the term “kursiyy”
This term has only been mentioned in the Quran once: “...وسع کرسیه السماوات و الارض...” (His throne expands over the heavens and earth). There are also several possibilities on what is truly meant by this verse:
1- The kursiyy is the location of where the dominion of Allah (swt) is located and refers to the rank of Allah’s (swt) governing and command, meaning that Allah (swt) rules all of the heavens and earth and has control over all things. Therefore, His kingdom encompasses all of the material world, which consists of the stars, earth, galaxies and nebulas. According to this definition for kursiyy, the arsh will be higher than the material world. In this case, the arsh will cover the world of the angels and souls and the metaphysical world.
2- The second possibility is that the term is referring to what Allah (swt) can have knowledge of, and in other words, the heavens and earth; nothing can escape His knowledge.
This interpretation is corroborated by a hadith by Imam Sadiq (as). He was asked about what is meant by “kursiyy” in the verse “وسع کرسیه السماوات والارض” and he answered: “His [Allah's (swt)] knowledge.” Regarding the meaning of kursiyy, the imam (as) has also said: “و الکرسی هو العلم الذی لم یطلع الله علیه احداً من انبیائه و رسله و حججه” (The kursiyy is Allah’s (swt) exclusive knowledge that no one, not even His prophets and apostles will ever become aware of).
3- The third possibility is that the kursiyy refers to a thing broader and vaster than all the heavens and earth that encompasses all of them.
Imam Ali (as) was asked of the kursiyy, he answered:”الکرسی محیط بالسماوات و الارض و ما بینهما و ما تحت الثری” (It encompasses everything on top of the earth and the heavens and everything in between these two and under the ground)
As can be seen, in this hadith the kursiyy has also been considered an actual thing that exists.
According to the writers of Tafsir Nemouneh there is no contradiction between these three meanings, and all three can be taken into consideration regarding the meaning of the verse, because “kursiyy” in the verse can be pointing to Allah's (swt) never-ending power and command, His never-ending knowledge of all things and to a realm and world vaster than our universe that encompasses ours all at the same time.
 Abdul-Karim Safipour, Muntahal-Arb, vol.3 and 4, under the letter “ع” pg.1716.
 Raghib Isfihani, Mufradat Alfadhil-Quran, root word of “عرش”
 Abdul-Karim Safipour, Muntahal-Arb, vol. 3 and 4, under the letter “ک”, pg. 1090.
 Mohammad Taqi Misbah Yazdi, Ma’arefe Quran, vols. 1-3, pg. 248.
 Baha’uddin Khorramshahi, Daneshnameye Quran, vol. 2, pp. 1445-1446.
 Mohammad Taqi Misbah Yazdi, Ma’arafe Quran, vols. 1-3, pp. 249-250.
 Morad Ali Shams, Ba Allameh dar Al-Mizan, vol. 2, pp. 165-166/
 Tawhid Saduq, pp. 321-322, hadith 1, chapter 50.
 Al-Mizan (translation), vol. 8, pg. 206.
 Tawhid Saduq, pg. 321-322., hadith 1, chapter 50.
 Al-Durrul-Manthur, vol. 3, pg. 477; Biharul-Anwar, vol. 55, pg. 210.
 Tafsir Nemouneh, vol. 2, pp. 200-201.
 Al-Mizan (translation), vol. 2, pg. 513; Tafsir Nemouneh, vol. 2, pp.
 Al-Tawhid, pg. 327.
 Ma’anil-Akhbar, pg. 29, hadith; Tafsir Burhan, vol. 1, pg. 240, hadith.
 Tafsir Nurul-Thaqalain, vol. 8, pg. 260, hadith 1042.
 Tafsir Nemouneh, vol. 2, pp. 200-201.
 Tafsir Nemouneh, vol. 2, pp. 200-201.