(noun)
a person or agency that offers assistance with fulfilling someone's personal business, such as running errands, scheduling appointments, and making travel reservations;
e.g. He hired a concierge to help him with the administration of his business.
(noun)
a resident of a block of apartments or a small hotel who serves as the caretaker, checking the comings and goings of people, performing/arranging maintenance, and representing the landlord, especially in France;
e.g. I called the concierge of my apartment building because my stove was not working.