Month

Among the Egyptians the month of thirty days each was in use long before the time of the Exodus, and formed the basis of their calculations. From the time of the institution of the Mosaic law the month among the Jews was lunar. The cycle of religious feasts depended on the moon. The commencement of a month was determined by the observation of the new moon. The number of months in the year was usually twelve (1 Kings 4:7; 1 Chr. 27:1-15); but every third year an additional month (ve-Adar) was inserted, so as to make the months coincide with the seasons. "The Hebrews and Phoenicians had no word for month save 'moon,' and only saved their calendar from becoming vague like that of the Moslems by the interpolation of an additional month. There is no evidence at all that they ever used a true solar year such as the Egyptians possessed. The latter had twelve months of thirty days and five epagomenac or odd days.", Palestine Quarterly, January 1889.

ירחים, sometimes also called חדשים, _new moons_, from the circumstance of their commencing with the new moon, anciently had no separate names, with the exception of the first, which was called _Abib_, that is, the month of the young ears of corn,” Exod. xiii, 4; xxiii, 15; xxxiv, 18; Deut. xvi, 1. During the captivity, the Hebrews adopted the Babylonian names for their months; which were as follows, and they were reckoned thus:-- 1. ניסן, _Nisan_, from the new of April, Neh. ii, 1. moon 2. זיו, _Zif_ or _Ziv_, also of May, 1 Kings vi, 1. called אייר, 3. סִיוָן, _Sivan_, of June, Esther viii, 9. 4. תמוז, _Tammuz_, of July. 5. אב, _Ab_, of August. 6. אלול, _Elul_, of September, Neh. vi, 15. 7. תשרי, _Tishri_, also ירח of October, 1 Kings viii, 2. האתנים, 8. בול, _Bul_, also מרחשון, of November, 1 Kings vi, 38. 9. כסלו, _Kislev_, of December, Neh. i, 1. 10. טבת, _Tebeth_, of January, Esther ii, 16. 11. שבט, _Shebat_, of February, Zech. i, 7. 12. אדר, _Adar_, of March, Esther iii, 7. The first month here mentioned, _Nisan_, was originally called _Abib_. The intercalary month is denominated in Hebrew אדר.