This is the 2126th most frequent Russian word.
цахал
The word "цахал" is not Russian; in Hebrew (צַהַ"ל, Tzahal), it refers to the Israel Defense Forces (IDF).
In this sentence, 'Цахаль' specifically refers to the Israel Defense Forces through its abbreviated term.
Цахаль — сокращение от Цва ха-Ганах Ле-Исраэль.
The term 'Tsahal' is an abbreviation for 'Tzva haHagana leIsrael'.
Here, 'Цахал' is used as a proper noun, specifically denoting the Israel Defense Forces.
Все израильские граждане обязаны пройти службу в Цахале.
All Israeli citizens are required to serve in Tsahal.
In this sentence, 'Цахал' is referred to as the organization or military force where the brother is employed.