An unofficial barrier to workplace advancement, usually in regard to women or minority groups.
Architectural textbooks have many references to ceilings made of glass. Of course, that's not what we are interested in here, although the fact that glass ceilings existed in the real world did lay the groundwork for the figurative phrase.
The term, in the barrier to advancement sense, was used by several writers on the topic of women in the corporate workplace during the 1980s; for example, Alice Sargent, in an interview about her book The Androgynous Manager, with the Washington Post in 1987:
"Women in corporate America are bumping their heads on the glass ceiling."
The earliest citation in print that we can find is from an article by Nora Frenkiel about magazine editor, Gay Bryant - "The Up-and-Comers; Bryant Takes Aim At the Settlers-In.", Adweek Special Report; Magazine World, March, 1984:
"Women have reached a certain point -- I call it the glass ceiling. They're in the top of middle management and they're stopping and getting stuck. There isn't enough room for all those women at the top. Some are going into business for themselves. Others are going out and raising families."
Since becoming commonplace in contemporary language it has become generally applied to obstacles encountered in any field and by any group; for example, this piece of economic news from the Daily Telegraph, 1994:
"After several spirited assaults, the FT-SE's 3200 glass ceiling finally gave way yesterday, allowing the index to close sharply higher after a day of drifting."