Islamic Calender -التقويم الهجري

The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; also called the Hijri calendar) is the calendar used to date events in many Arab Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate Islamic holy days. It is a lunar calendar having 12 lunar months in a year of about 354 days. Because this lunar year is about 11 days shorter than the solar year, Islamic holy days, although celebrated on fixed dates in their own calendar, usually shift 11 days earlier each successive solar year, such as a year of the Gregorian calendar. Islamic years are also called Hijra years because the first year was the year during which the Hijra occurred— Prophet Muhammad's(PBUH) emigration from Mecca to Medina. Thus each numbered year is designated either H or AH, the latter being the initials of the Latin anno Hegirae (in the year of the Hijra).
The Islamic months are named as follows from pagan times.Their names are derived from and relevant to occurances in pre-Islamic tribal Arabia:
Muharram محرّم (long form: Muuarram ul Haram)
Safar صفر (long form: Safar ul Muzaffar)
Rabi' al-awwal (Rabī' I) ربيع الأول
Rabi' al-thani (or Rabī' al Thānī, or Rabī' al-Akhir) (Rabī' II) ربيع الآخر أو ربيع الثاني
Jumada al-awwal (Jumādā I) جمادى الأول
Jumada al-thani (or Jumādā al-akhir) (Jumādā II) جمادى الآخر أو جمادى الثاني
Rajab رجب (long form: Rajab al Murajab)
Sha'aban شعبان (long form: Sha'abān ul Moazam)
Ramadan رمضان (long form: Ramadān ul Mubarak)
Shawwal شوّال (long form: Shawwal ul Mukarram)
Dhu al-Qi'dah ذو القعدة
Dhu al-Hijjah ذو الحجة
Meaning of the months:
1.Muharram( a holy month where no warfare or fighting is allowed)
2.Safar (Safar literally means ‘the void month’as when the pagan Arabs went on their looting expeditions or persued tribal reprisals or wars since they could not do that in the four sacred month,they would leave their houses would be empty or ‘sifr’ meaning void.
3.Rabia al awal ("First spring")
4. Rabia Thani ("Second spring")
5. Jumaada Awal ("First freeze")
6. Jumaada Thani ("Second freeze")
7. Rajab ("To respect" - this is another holy month when fighting is prohibited)
8. Sha'ban ("To spread and distribute")
9. Ramadan ("Parched thirst" - this is the month of daytime fasting)
10. Shawwal ("To be light and vigorous")
11. Dhul-Qi'dah ("The month of rest" - another month when no warfare or fighting is allowed)
12.Dhul-Hijjah ("The month of Hajj" - this is the month of the annual pilgrimage to Mecca, again when no warfare or fighting is allowed)
Days of the week are named:
yaum al-ahad يوم الأحد (first day - Sunday)
yaum al-ithnayn يوم الإثنين (second day - Monday)
yaum ath-thulaathaa' يوم الثُّلَاثاء (third day - Tuesday)
yaum al-arbia`aa' يوم الأَرْبِعاء (fourth day - Wednesday)
yaum al-khamis يوم الخَمِيس (fifth day - Thursday)
yaum al-jumu`a يوم الجُمُعَة (gathering day - Friday)
yaum al-sabt يوم السَّبْت (Saturday)