When I see this word, the first thing that pops into my mind is the term "ladies auxiliary", because the women usually have a support group for men's fraternal organizations, and in the past occupations that were mainly male, such as the fire or police auxiliary.  I'm not sure if they still have those, since women now serve in both the fire and police departments.  

Auxiliary often refers to several types of ships that accompany task groups of naval vessels. These ships can be oilers, repair ships, floating dry-docks, ammunition ships, hospital ships, supply ships, command ships, and refrigeration ships. Over the course of the US Navy's prosecution of the Pacific War (1941-45), they quickly discovered that handling the logistics of a fleet and opposed amphibious operations over thousands of miles was a real ball-buster of a problem. You can't accomplish the mission with your gear in the rear.

To make fleets work over the vast distances of the Pacific, these specialty ships had to be built. Existing merchant hulls were too slow and not equipped for these specific missions. Luckily, US yards were churning out liberty ship hulls at a prodigious rate. Some of these hulls were diverted to the Navy's for use as fleet train, and converted to fulfill their specific roles.

USS Mount McKinley (LCC-7) - was a late war amphibious command ship outfitted with the communications, supporting equipment and supplies to command amphibious landings. She served in that role until 1970.