The Old Testament uses three Hebrew words that are translated into the English word "prophet" or "seer": nabi, roeh, and hozeh.
Nabi literally means "to bubble up." It describes one who is stirred up in spirit. It is the most frequently used of the three by the Hebrew writers. When the sense of "bubbling up" is applied to speaking, it becomes "to declare." Hence, a nabi, or a prophet, is an announcer—one who pours forth the declarations of God.
Roeh means "to see" or "to perceive." It is generally used to describe one who is a revealer of secrets, one who envisions.
Hozeh also means "to see" or "to perceive," but is also used in reference to musicians. It is also used to describe a counselor or an advisor to a king. The Hebrew does not necessarily indicate that the person is a prophet, but rather an advisor—someone who has wisdom. It means "one who has insight." The translators try to indicate whether the message is spiritual. If it is spiritual, then they tend to translate hozeh as "prophet." If it does not give any indication of being spiritually generated, then they would render it "advisor" or "counselor.”
In the Greek language, a prophet is simply "one who speaks for another"—one who speaks for a god, and so interprets the god's will to the people. Hence, the essential meaning in Greek is "interpreter."
Nobody knows whether God intends that any real difference be understood from the usage of the different words, but biblical usage is more important than etymology. In the context of these scriptures, it defines a prophet about as well as possible. The conclusion is that a prophet is one who speaks for another, a representative who carries a message, an expounder of God's Word.
Overall, the Bible's usage conforms most closely to the Greek usage, one who speaks for another. But it is not limited to God. In this situation, Moses and Aaron's relationship is analogous to God and Moses'.