Koiak
fourth month of the moon calendar and the civil calendar in ancient Egypt and of the Coptic calendar
Koiak (; Coptic: Ⲕⲟⲓⲁⲕ, [ˈkɔjak]), also known as Choiak (Ancient Greek: Χοιάκ, Khoiák) and Kiyahk (Coptic: Ⲕⲓⲁϩⲕ, Kiahk, [ˈkijahk]; Arabic: كياك or كيهك), is the fourth month of the ancient Egyptian and Coptic calendars. It lasts between 10 December and 8 January of the Gregorian calendar, or between 11 December and 9 January of the Gregorian calendar in Coptic calendar years immediately following a Coptic calendar leap year (which occur every four years, in Coptic calendar years immediately preceding those that are divisible by 4 to produce an integer; i.e., 1719, 1723, 1727, 1731, etc. are all examples of leap years in the Coptic calendar).
The month of Koiak is also the fourth month of the Season of Akhet (Inundation) in Ancient Egypt, when the Nile floods historically covered the land. They have not done so since the construction of the High Dam at Aswan.
Name
The name of the month of Koiak comes from the Egyptian phrase kꜣ ḥr kꜣ "Soul upon Soul", a name of the sacred ancient Egyptian Apis Bull. It is attested in cuneiform with the pronunciation 𒆪𒄿𒄴𒆪 ku-i-iḫ-ku, likely representing /kɔʔ-iḥ-kɔʔ/ with an o-vowel as in later Coptic. It is also attested in Imperial Aramaic in the letters of Ananiah in the Jewish colony of Elephantine, Egypt as כיחך kyḥk.
Coptic tradition
The month of Koiak holds a special place in the rite of the Coptic Orthodox Church. It is known as the "Mariam Month" ("Month of Mary") because the Nativity according to the Coptic calendar falls on 29 Koiak.
“Koiak” enters the record as fourth month of the moon calendar and the civil calendar in ancient Egypt and of the Coptic calendar. Crown Archives preserves that source wording while asking what Koiak, fourth and month can confirm, complicate or overturn.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jun 24, 2026. The linked authority identifier is Q1410257. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1719, 1723, 1727 and 1731.
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