الاحد

In a sentence

• ذهبَ أحمد إلى المدرسة يوم الأحد.

  Ahmed went to school on Sunday.

  In this sentence, 'الأحد' (Sunday) is used to indicate the name of a specific day of the week.

• في ذلك الوقت لم يكن في العالم إلا أحد.

  At that time, there was no one in the world but one person.

  Here, 'أحد' (one person) is used within a negative construction to denote exclusivity.

• تحدثت مع أحد الأصدقاء أمس.

  I spoke with one of the friends yesterday.

  In this case, 'أحد' (one) notes an indefinite individual, demonstrating its usage as an indefinite pronoun.