دلیل

In a sentence

• دلیل موفقیت او، تلاش بیش از حد بود.

  The reason for his success was his excessive effort.

  Here, 'دلیل' is used as a noun meaning 'reason,' specifying the cause or purpose of success.

• به دلیل بارندگی زیاد، سفر ما لغو شد.

  Due to heavy rainfall, our trip was canceled.

  In this sentence, 'به دلیل' is a prepositional phrase meaning 'due to,' indicating the cause or reason for an event.

• او دلیلی نداشت که اعتراض کند.

  He had no reason to object.

  Here, 'دلیل' denotes justification or motive for an action, used in this example to refer to the reason for complaining.