What is Cinnamon and Cassia?

Cinnamon and Cassia are two different type of plants plants. However, now a days they are used interchangeably. In United States most of the ground cinnamon in reality is ground Cassia. In ground form, Cassia has a more robust flavor than Cinnamon.
Cinnamomum eylanicum: Cinnamon. In Hindi, it is called "Dalchini".
Native to Ceylon (Sri Lanka)
Cinnamomum aromaticum: Cassia. In Hindi it is called "Jungli Dalchini". Native to Burma.
Cinnamon and cassia both come from the bark of a plant in the laurel family. The Cinnamon is brown color; while Cassia is Reddish brown. Cinnamon is primarily use to make curries, Garam Masala, sweets, Garam Chai. .