mentor (n.)
A mentor is someone who guides a less experienced person. The word was a person’s name first.1
In Homer’s Odyssey, Mentor was a trusted friend of Odysseus. When Athena went to help Odysseus’s son Telemachus, she appeared in Mentor’s form. The advice came from the goddess, though the young man saw his father’s friend.12
Mentor took on a larger role in François Fénelon’s 1699 novel Les aventures de Télémaque. After that book, his name became a general word for a trusted guide in French and then in English.2
Her first editor became her mentor.