This is the 12264th most frequent Russian word.
ислама
The Russian word "ислама" is the genitive case of "ислам," meaning "of Islam."
Here, 'ислама' is in the genitive case and denotes a topic of interest.
Ислама интересует его история.
Islam is interested in its history.
In this context, 'ислама' refers to the religion Islam and is used in the genitive case as it follows 'основы' (foundations).
Мы изучаем основы ислама.
We study the foundations of Islam.
Here, 'ислама' is used in the genitive case after 'значении' (significance), denoting possession or association.