al-Salāmu ‘alaykum wa rahmatullāh,
As seen previously, the Arabic language is very precise in its lexical references owing to its rich vocabulary. Often a single concept may be taken – such as love, infancy, bravery etc – and different words found corresponding to the subtle differences in the degrees of that concept. And perhaps this is the basis of the Arabic maxim:
خَيْرُ الكلامِ ما قَلَّ ودَلَّ
The best of speech is that which has the fewest words while retaining the desired meaning
for only one well-versed in the subtleties of the vocabulary would be able to achieve this.
It is especially important to be aware of these subtleties when their words appear in the Qur'an, for only then can one understand the true nature of the message. In this regard, I present the degrees of sleep in Arabic:
1. al-nu'aas النُّعاس – this is when a person's eyes becomes tired or drowsy and feels the need for sleep. This word was used by Allaah when he gave the Muslims at the Battle of Badr a break before the fighting began to strengthen them, as mentioned in al-Anfal, verse 11,
إِذْ يُغَشِّيكُمُ النُّعَاسَ أَمَنَةً مِّنْهُ وَيُنَزِّلُ عَلَيْكُم مِّن السَّمَاء مَاء لِّيُطَهِّرَكُم بِهِ وَيُذْهِبَ عَنكُمْ رِجْزَ الشَّيْطَانِ وَلِيَرْبِطَ عَلَى قُلُوبِكُمْ وَيُثَبِّتَ بِهِ الأَقْدَامَ
[Remember] when He covered you with a slumber as a security from Him, and He caused rain to descend on you from the sky, to clean you thereby and to remove from you the whisperings of Satan, and to strengthen your hearts, and make your feet firm thereby.
It is interesting to note that al-nu'aas was sent to them as opposed to al-wasan, perhaps indicating that while their eyes were given the chance to sleep and rest, their minds remained fit and alert. And Allaah knows best.
2. al-wasan الوَسَن – this is when the tiredness intensifies in the head, and it becomes heavy with its need for sleep. Some linguists said the distinction between al-wasan and al-nu'aas is extremely slight in degree, and they only differ in their place (al-nu'aas in the eyes, and al-wasan in the head). The verbal noun is sinah سِنَة as in al-Baqarah, verse 255,
اللّهُ لاَ إِلَـهَ إِلاَّ هُوَ الْحَيُّ الْقَيُّومُ لاَ تَأْخُذُهُ سِنَةٌ وَلاَ نَوْمٌ
Allah! none has the right to be worshipped but He, the Ever Living, the One Who sustains and protects all that exists. Neither tiredness (sinah), nor sleep overtake Him.
3. al-tarneeq الترنيق which is when sleep pervades a person, without him actually sleeping.
4. al-ghumd الغُمض which is a state between sleep and wakefulness.
5. al-taghfeeq التَّغْفيق which is a state of sleep in which one still able to hear what others say.
6. al-ighfaa' الإغْفاء which is a very light sleep.
7. al-tahweem التهويم or al-ghiraar الغِرار or al-tihjaa' التهجاع all of which refer to a sleep of short duration.
8. al-ruqaad الرُّقاد which refers to a very long sleep, as in al-Kahf, verse 18,
وَتَحْسَبُهُمْ أَيْقَاظاً وَهُمْ رُقُودٌ
And you would have thought them awake, while they were asleep
and Yaseen, verse 52, 
قَالُوا يَا وَيْلَنَا مَن بَعَثَنَا مِن مَّرْقَدِنَا هَذَا مَا وَعَدَ الرَّحْمَنُ وَصَدَقَ الْمُرْسَلُونَ
They will say: "Woe to us! Who has raised us up from our place of sleep." (It will be said to them): "This is what the Most Beneficent (Allah) had promised, and the Messengers spoke truth!"
9. al-hujood الهُجود or al-hujoo' الهجوع or al-huboo' الهبوع which refer to a very deep sleep.
10. al-tasbeekh التسبيخ which refers to the strongest, deepest type of sleep.
11. al-subaat السبات which refers to a coma. 
 The marqad مرقد is the noun of place from the same root ر ق د.
 al-tasbeekh comes from the root س ب خ. In light of the previous post on ishtiqaaq note the relationship between the meaning of the word tasbeekh from this root, and the word subaat from the root س ب ت.