Translation, please! (Arabic)

What does the word ‘Mujahidin’ mean? Is it a word, or just a name? (I used the AP spelling. I hope that’s pretty standard.)

Mujahidin means “people of the jihad” or “crusaders”.
Note that the Arabic In ( pronounced and sometimes spelled in English as een ) is a plural noun meaning “people”.
Bedouin ( people of the desert ) was assimilated incorrectly into English as singular.
I am not sure if Mujahidin is also (mis)used in English to refer to a single crusader.

Correct, but the bit about Bedouin being mis-translated ? I thought Bedouin wasn’t really singular, but represented the collective, as in He is [a] Bedouin, or Nez
Perce, etc… I’ve never seen anyone refer to Bedouins.

From the New Shorter Oxford English Dictionary

This is the word that Ronald Reagan used to refer to the guerillas who fought against Soviet forces in Afghanistan in the 1980s.

I was surprised that I got to answer. My knowledge of Arabic is nonexistent.
I do know that “He is a bedouin” would be improper in that language, unlike in English.
I do not know if “He is Bedouin” would be proper in Arabic. To use the example of the OP:
The plural is “mujahidin” (mujAhidIn) and the singular is “mujahid” (mujAhid).