What we call "black tea" is known in much of Asia as "red tea"—referring more to the color in the cup than the blackened appearance of the fully oxidized leaves before brewing. It may also be useful to distinguish between the origins of black teas, such as Chinese (whose leaves are picked earlier and withstand more oxidation) and black teas of other origins, e.g. Africa, India and Sri Lanka (whose leaves are picked later and are less oxidized). The difference in processing methods of these teas is reflected in their flavor, and affects the way in which you may choose to brew them.
'Ceylon' on Serious Eats
Most of what we enjoy and call cinnamon in the U.S. is Cinnamomum aromaticum or C. loureiroi, also known as cassia. It's the brash, bold, sweet-and-spicy stuff we love in our cinnamon buns and gingerbread. But it's not the only cinnamon out there. In the past, when people talked about cinnamon, they were talking about C. verum (née C. zeylanicum when Sri Lanka was called Ceylon). It's not the cinnamon Americans are used to—it's much more mellow and subtle—but it's worth expanding our horizons for.