This is the 6388th most frequent Arabic word.
اتحاده
"Its union" or "its federation."
'اتحاده' here refers to his specific union or organization he belongs to. It is used possessively to tie the union to him.
عليه أن يدعم اتحاده في العمل.
He must support his union at work.
The usage of 'اتحاده' in this sentence focuses on the qualitative aspect of his union, emphasizing its strength as a contributing factor to his success.
نجاحه يعود إلى قوة اتحاده وإصراره.
His success is attributed to the strength of his union and his determination.
The word 'اتحاد' refers to a union or organization that gathers individuals for a common purpose. In this context, 'اتحاده' would imply the state or condition of his or their union.