When the month of Shaban comes, a sensation of joy and happiness spreads among Muslims. Shaban signals the coming of Ramadan, the best and most blessed month in Islam.
Therefore, full of joy, hope and optimism, Muslims start spiritual preparation for Ramadan during this month. They make plans; set goals and targets; prepare lists of worships to do and pray that Allah bless them with the opportunity to witness Ramadan and benefit from it.
Shaban is the 8th month of the Islamic lunar calendar called the hijri calendar.
The Arabic month names were known before the advent of Islam. There are reports that these names were introduced by Kilab ibn Murrah, the 5th grandfather of the Prophet (peace and blessings be upon him).
The months’ names reflected the prevailing social practices and weather conditions at the time. For example, it is reported that the name of the month of Ramadan was derived from “ramadha” which indicates intense heat; Ramadan was named so because it coincided with the severe heat of summer.
So, there are some explanations of the name of the month of Shaban. The word Shaban is derived from the root “sha `a ba” which has a number of meanings including branching and separating.
In view of these two meanings, we find a number of explanations of the reasons of naming Shaban so. It is reported that Shaban was named so because:
One of the names of Shaban is Al-`Ajlan, which means the fast or quick month. It is called so because people feel that it flies fast and that the next month, Ramadan, comes very quickly.
Subh Al-Asha, Abi Al-Abas Al-Qalaqshandi 2/365
Lisan Al-Arab, Ibn Manzur 1/502
SOURCE: https://aboutislam.net/shariah/special-coverage-shariah/what-is-the-meaning-of-shaban/
