Days
From the remotest time to the present the Israelites have computed the day (yôm) from sunset to sunset, or rather from sunset to the appearance of the first three stars which marked the beginning of a new day [Cf. Lev. 23:32; II Esd. (Nehem.) 4:21; etc.]. Before the Babylonian Exile the time between sunrise and sunset was divided into "morning", "midday", and "evening" (Psalm 54:18; Hebrew 55:17); but during the stay in Babylon the Hebrews adopted the division into twelve hours (Cf. John 11:9), whose duration varied with the length of the day. On an average, the first hour corresponded to about 6 a.m.; the third hour to 9 a.m.; the end of the sixth to noon; while at the eleventh the day was near its close. Earlier than this division of the day by hours was that of the night into three watches: the first till midnight; the second or middle watch (cock-crow) till 3 a.m.; and the third or morning watch till about 6 a.m.
Weeks
Seven consecutive days form the week, or second element of the Jewish calendar. As in our ecclesiastical calendar, the days of the Jewish week are numbered, not named. They are called the first day, the second day, the third day, and so on to the seventh, which last is also called "sabbath" (shábbath) a name likewise used to designate the week itself. The sixth day, our Friday, is also known in the New Testament, in Josephus, and in Rabbinical writings as "the eve of the sabbath", or as "the day of the preparation", the paraskeué, a term still employed by the Latin Church in connection with Good Fridays (Cf. Mark 15:42; Josephus, Antiquities of the Jews, XVI, 6:2; Talmud of Jerusalem, Treatise Pesahîm, chap. 4:I).
Months
The third and most important element in the Jewish arrangement of time is the month. The two Hebrew words for month are yéráh, and hodésh, whose primitive meaning, "moon", "new moon", points to the dependence of the Jewish month on the phases of the moon. As a matter of fact, the Hebrew months have always been lunar, and extended from one new moon to another. The beginning of the month with the appearance of the new moon was--as it is still--of great practical importance among the Hebrews, inasmuch as the first of every month was to be observed as New Moon's Day, and certain feasts were affixed to the 10th, 14th, or other days of the month. The earliest appearance of the new moon was long ascertained by direct observation, and authoritatively settled by a commission of the Sanhedrin, and the intelligence then made known to the Jews at large, first by means of fire signals, and later on through special messengers. In the present day, and for many centuries, this very primitive manner of fixing the beginning of the month has given way to a systematic calculation of the latter's duration, and the Jewish calendar is now constructed on the basis of a mean lunation of 29 days, 12 hours, 44 min., and 30 sec. Besides being indicated by means of numerals, the first month, the second month, etc., the Hebrew months have been designated in the course of Jewish history by two sets of names. Of the former set--going back probably to Chanaanite times--only four names have survived in the Hebrew Bible. These are: 'Abhîbh (A.V. Exodus 13:4, 23:15; Deuteronomy 16:1), subsequently the first month; Zíw (1 Kings 6:1), subsequently the second month; 'Ethanîm (1 Kings 8:2), subsequently the seventh month; and Bûl (1 Kings 6:38), subsequently the eighth month. The latter set of names, certainly of Babylonian origin, began to be used after the Exile. Of its twelve names now found in the Jewish calendar only seven occur in the Hebrew text, but the whole twelve appear as the main divisions of the Megillath Ta'anith (Scroll of Fasting), which in its original form is referred to a date before the Christian Era. These twelve names are as follows:
1. Nîsan (Nehemiah 2:1; Esther 3:7)
2. 'Iyyar (not named in Scripture)
3. Sîwan (Esther 8:9; Baruch 1:8)
4. Támmûz (Cf. A.V. Ezekiel 8:14)
5. 'Abh (not named in Scripture)
6. 'Elûl (Nehemiah 6:15; 1 Maccabees 14:27)
7. Tíshrî (not named in Scripture)
8. Márhéshwan, or simply Héshwan (not named in Scripture)
9. Kíslew (Zechariah 7:1; Nehemiah 1:1)
10. Tebeth (Esther 2:16)
11. Shebhat (Zechariah 1:7, 1 Maccabees 16:14)
12. 'Adar (Ezra 6:15; Esther 3:7, 8:12, etc.)
Catholic Encyclopedia
