Character 禪 has two sounds. One of the sounds is chán. When it makes chán sound, if we check its meaning in Chinese English dictionaries, it has the meanings: zen, Buddhist, meditation, contemplation, etc.
The original meaning of Character 禪 is ' to pray to God for peace by offering sacrifice to the heaven' (祭天求神，祈求避免争端和战乱，赐予人间和平和安宁).
I checked the vividict.com (象形字典). It says the left part of this character means 'to offer sacrifice, to pray',
while the right part of this character means 'war'.
This character was used by Chinese Buddhists when the Buddhism was introduced into China from India, as the sound of the character 禪 chán was close to the sound of Sanskrit word for 'meditation'. Zen, or meditation, which is also a way to pray for peace of mind, to cease or avoid the war of turbulence inside.
The earliest script of this character is the Bronze script（金文 jīn wén ）:
The following video will show you how to write this character in Bronze script.
In modern days, there are still three types of script are wildly used in our daily life. Now I am going to show you how they look like and how to write them with brush.
The Regular Script（楷书 kǎi shū ）:
How to write this character in regular script:
The Semi-cursive Script（行书 xíng shū ）:
How to write this character in Semi-cursive script:
The Cursive Script （草书 cǎo shū ）:
How to write this character in Cursive script:
禪 is the traditional character. 禅 is the correspondent simplified character, which is used in main land China. Maybe you already noticed that the simplified character comes from the one written in the semi-cursive script.