In English speaking countries, where we use the word tea to talk about the drink made with leaves from the plant, Camellia sinensis, we tend to think of chai as tea, the way it is made in India, with the spices. But, really, there are many languages where "chai" just means the same thing as "tea" does in English. It's not like we only call it tea when it is made with Camellia sinensis leaves. We have herbal teas and some of those don't involve leaves, e.g., chamomile tea is made with flowers, as are rosehip and hibiscus. And Constant Comment Tea has some orange rind as well as some spices. Did you have a look at the article I linked?