This is the 2639th most frequent Arabic word.
العاشر
The tenth.
In this sentence, 'العاشر' is used as an ordinal number to signify the tenth level within a series (grades).
وصلت إلى الصف العاشر هذا العام.
I reached the tenth grade this year.
Here, 'العاشر' denotes the position of the day within the sequence of days in a month (ordinal usage with dates).
كان الاحتفال في اليوم العاشر من الشهر.
The celebration was on the tenth day of the month.
In this example, 'العاشر' is part of a time expression, pointing to the time (10 AM) in a sequence of hours.