This is the 1443rd most frequent Russian word.
защиту
"Защиту" (accusative case of "защита") – "protection" or "defense."
In this sentence, 'защиту' refers to 'protection' or 'defense' in the context of advocating for rights.
Он боролся за защиту своих прав.
He fought for the protection of his rights.
Here, 'защиты' denotes the act or means of safeguarding the building, translated as 'protection'.
Для защиты здания установили современные системы безопасности.
Modern security systems were installed for the protection of the building.
In this context, 'защиту' is translated as 'defense' and refers to the formal presentation and justification of one's thesis.