Aide

.
an aide-de-camp.
an assistant or helper, especially a confidential one.
Contemporary Examples

The aide is Christopher Michel, a 28-year-old former White House speechwriter.
Bush’s Ghostwriter Bryan Curtis March 8, 2010

After the event, she even scheduled a lunch date with an aide.
Leading the Anti-Bachmann Army David A. Graham July 18, 2011

They apologized for “poor judgment,” then essentially retracted the apology by claiming Wolf’s aide was provoked.
Virginia Republicans Haven’t Learned Paul Begala October 28, 2008

Allen, once an aide to the late Senator Jesse Helms, resigned in 2006 after he was arrested for felony thefts from retail stores.
Rick Warren’s Africa Problem Max Blumenthal January 6, 2009

An aide said the Prince had been “deeply touched” by Mrs Marley’s gift.
You Will See Diana Again, Bob Marley’s Widow Tells Harry As Prince Dances To ‘One Love’ March 6, 2012

Historical Examples

He turned toward his aide lazily and asked: “Suppose there had been two taxi-cabs instead of one that night?”
Ashton Kirk, Secret Agent John T. McIntyre

An aide arrived with an order to Hertford, and then he loosed his eager cavalry.
The Rock of Chickamauga Joseph A. Altsheler

An aide appeared in the doorway of the room in which were gathered McClellan and several of his generals.
The Long Roll Mary Johnston

“We ought to be in the City of Mexico in a day or two, sir,” resumed the aide.
The Strollers Frederic S. Isham

Exhibit No. 21 is a summary of the activities of Pat Hutton, who is an aide in the emergency room.
Warren Commission (6 of 26): Hearings Vol. VI (of 15) The President’s Commission on the Assassination of President Kennedy

noun
an assistant
(social welfare) an unqualified assistant to a professional welfare worker
short for aide-de-camp
n.

1777, short for aide-de-camp (1660s), French, literally “camp assistant” (see aid (n.)).