This is the 3rd most frequent Latvian word.
ar
The Latvian word "ar" means "with" in English.
Here, 'ar' is used to indicate companionship, meaning 'with'.
Es eju uz saimniecības veikalu ar tēvu.
I am going to the hardware store with my father.
Here, 'ar' is used to indicate a cause or reason, meaning 'for' in this context.
Viņš ir slavens ar savu talantu.
He is famous for his talent.
Here, 'ar' is used to indicate the means or instrumentality, meaning 'with' as in 'by means of'.