This is the 3915th most frequent Arabic word.
ال
"ال" is the definite article in Arabic, equivalent to "the" in English.
The word 'المدرسة' uses 'ال' as the definite article, indicating a specific school.
ذهبتُ إلى المدرسة.
I went to the school.
The word 'الكتابَ' uses 'ال' as the definite article, indicating a specific book, and 'المفيدَ' has 'ال' to specify the quality.
قرأتُ الكتابَ المفيدَ.
I read the useful book.
The word 'الجوُّ' uses 'ال' as the definite article, indicating the specific weather, and 'اليومَ' also uses 'ال' for specificity.