Marcheshvan
Proper noun
Meaning
Marcheshvan
(Judaism) Cheshvan
Examples
In a malei ("filled") year, the month of Marcheshvan is increased to 30 days. 13-month years follow the same pattern, with the addition of the 30-day Adar Alef, giving them between 383 and 385 days.
The month you ask about is consistently referred to in halachic discussions as Marcheshvan, not Cheshvan.