"chai/cāy" is "tea" in Hindi, just as cha is the word for tea in Chinese (where the word comes from). Trendy non-Indian businesses in US, at one point, began to offer tea prepared in the Indian "masālā" (spiced) style, under the label of "chai". I remember working in a cafe in the mid-1990s, which is when I believe the American "chai" thing was introduced. We had some kind of prepackaged, syrupy mixture of sugar and the spice flavors and milk, which was blended into prepared Sri Lankan tea. Needless to say, that's not how any tea is prepared in India, but the specific "flavor" of the mixture became the industrial standard in the US for things labeled as "chai", just like "pumpkin spice" is a flavor. Tea in India is typically prepared by boiling the leaves (and spices, if any) rather than pouring sub-boiling water over the leaves (which is the proper method in China, where individual teas are enjoyed for their natural flavor). The idea seems to be to just boil leaves to death to drain out their pungency as a thing to cut through milk and sugar... hence to me, the connotation of "chai" is not the masala (which is very often omitted) but that whole boiled / milky thing.