This is the 9381st most frequent Japanese word.
礼文島
Rishiri Island is an island in Hokkaido Japan
In this sentence, '礼文島' is used as a proper noun to refer to the geographic location known as Rebun Island.
礼文島は日本の領土にある島です。
Rebun Island is an island located within Japan's territory.
Here, '礼文島' is used as a possessive noun to describe the location whose flowers are the focus.
礼文島の花々は春に特に美しいです。
The flowers of Rebun Island are especially beautiful in spring.
In this instance, '礼文島' is used as a direct object, specifying the destination to be visited.