In business, a glass ceiling is an invisible barrier that prevents women or minorities from advancing beyond a certain level. The glass ceiling may have kept your grandmother from her dream of running a large company.
The glass ceiling is a metaphor for a systemic issue: the ceiling forces a person to stop advancing, but it's invisible, so an employer can pretend it doesn't exist. It has historically been a very real obstacle to progressing within any hierarchy, including politics and academia. Kamala Harris broke a glass ceiling by becoming the first Black woman vice president of the United States in 2020, and Sally Ride did too, as the first American woman in space in 1983.