What is the meaning of AL in Arabic?

"AL" in Arabic has no meaning on its own. It is a definite article, equivalent to "the" in English. It's always attached to a noun and serves to specify or define the noun.

For example:

* Al-kitab (الكتاب) means "the book"

* Al-qalam (القلم) means "the pen"

* Al-madina (المدينة) means "the city"

So, "AL" itself doesn't have a meaning, but it adds specificity to the noun it's attached to.