An advisory is an announcement that often gives a warning, like a weather advisory about a blizzard. An advisory job involves giving advice.
People like to give advice: friends, family, writers, and TV personalities are constantly giving tips about saving money, losing weight, and finding love. An advisory is a type of advice that is specific and usually important, like an announcement of bad weather or a terrorist threat. Advisories are often issued by the government as warnings. Also, someone whose job is to give advice has an advisory position.