This is the 8022nd most frequent French word.
tatarstan
"Tatarstan" is not a French word; it refers to a federal subject (republic) of Russia.
Here, 'Tatarstan' refers to the proper noun denoting a region.
Le président de Tatarstan a visité la capitale.
The president of Tatarstan visited the capital.
In this usage, 'Tatarstan' is discussed as a subject of study or context.
J'ai lu un livre fascinant sur l'histoire de Tatarstan.
I read a fascinating book about the history of Tatarstan.
Here, 'Tatarstan' is used to denote the origin of the people and culture being described.