NO BULL

In the Torah the months have no names.They are

numbered (1st, 2nd etc.) except for Nissan which is called  

Chodesh Ha'aviv.

In Tanach we find different names for some months.

 ניסן = אביב, אייר = זיו,  תשרי = ירח האתנים, מרחשון= בול

The months אלול,כסליו,טבת,שבט,אדר & ניסן appear in 

Tanach (as is)

Chodesh Cheshvan in Tanach (Melochim 1:6:38 is referred

to  as ירח בול  month of Bul.

The Midrash (Tanchuma) writes that after the Mabul

it used to rain heavily for 40 days starting from Rosh

Chodesh Cheshvan. Shlomo Hamelech after completing

the Bais Hamikdash davened for the rain to stop.

Therefore the מ from מבול was removed and changed 

to בול. (The month the Bais Hamikdash was completed)

   

The Pri Chadash writes if a Get was dated ירח בול it is

a kosher Get

The Rema (Hl. Gittin 126 :6) writes to spell the month

מרחשון  (not חשון ) in a Get.

The Poskim (Pischei Teshuva- Get Poshut)  rule if it was written  חשון “      

it is Kosher B’dieved.

Harav Hagaon R. Y.S. Elashiv zt"l ruled , If a Rosh Yeshiva,

Rov etc. was Mesader with a Kesubah spelled “ חשון “ ,    

since B’dieved it is Kosher, you should not embarrass him

to correct his mistake.