We'll just have to chalk it up to slight deviation in word use in an alien language.
Those wacky Bajorans. After all, they also refer to an hourglass-shaped object as an orb.
Another good observation! Funny Bajorans.
"Prophet" also means "someone who foretells the future." Think of "prophecy," whose primary meaning is a prediction of future events, usually divinely inspired, e.g. the alleged prophecies of Nostradamus. The wormhole aliens exist outside of time, perceiving past, present, and future as one, and thus they can reveal the future (or the past) to the Bajorans through Orb experiences, i.e. prophecies.
I like that explanation and it makes a lot of sense. Thanks.