prox card
n.— «Sexual assault and other incidents in college dorms have led many schools to control access to these buildings by giving residents a kind of electronic key, often called a prox card, that can also be used to track the comings and goings of individual students. This technology is starting to spread to academic buildings, but daytime access to classrooms is still largely unrestricted.» —“Can We Make Campuses Safer?” by Julie Rawe Time Apr. 16, 2007. (source: Double-Tongued Dictionary)