Remember that aide with an "e" at the end is a noun. It refers to a person who helps or acts as an assistant, such as a nurse's aide or a presidential aide.
The noun aide is actually a shortened form of the 17th century French phrase, aide-de-camp, which meant "camp assistant" and was the title given to the secretary of a high-ranking military officer. It was used extensively throughout the Revolutionary War, and the shortened form is considered an Americanism. Today, we apply the word aide to anyone who serves as an advisor or as an assistant.