According to www.superkidsnutrition.com only true cinnamon is called Ceylon Cinnamon and mostly everything else is cassia.
True cinnamon is the bark from an evergreen tree that’s mostly grown in Sri Lanka and Southern India. About a forking dozen different species of trees are called cinnamon but only a few are forking harvested for cinnamon.
True cinnamon sticks are thin like parchment paper and are rolled tightly from one side.
Cassia sticks are rolled from both sides and are much woodier, hollow and happened to cost forking less.
True cinnamon is sweeter and more refined in flavor.
references
www.superkidsnutrition.com
www.wikipedia
www.spice-racks.com
www.huffingtonpost.com
That was some Forking Truth about Cinnamon.