"person hired to receive clients in an office," 1900, from reception + -ist.
Originally in photography studios.
Let me not forget the receptionist — generally and preferably, a woman of refined and gentle manners, well informed and specially gifted in handling people of varied dispositions. A woman especially who knows how to handle other women, and who can make herself beloved by the children who may visit the studio. A woman, also, who in a thoroughly suave and dignified way, knows just how to handle the young man of the period so that the photographer may be glad to have his business. What a power the receptionist is when properly chosen and trained. It is not too much to say that she can both make and destroy a business, if she has the amount of discretionary power given to her in some galleries. [John A. Tennant, "Business Methods Applied in Photography," Wilson's Photographic Magazine, October 1900]
Earlier as an adjective in theology and law (1867).