The first pager was invented in 1921 for use by the Detroit Police Department, but back then they were called beepers and they weren't commercially viable until the 1950s, when the word pager first began to be used in advertising. This term is a noun form of the verb page, which had a definition of "summon someone by name" and has been around since 1904. For a good four hundred years before that, it also meant "attend to", which comes from a previous noun page, meaning "errand boy". Through Old French and maybe Italian, that derives from Latin pagius ("servant"), which traces to Ancient Greek pais, meaning "child". Finally, philologists reconstruct it all as being from the reconstructed Proto-Indo-European root pehw, or "little". There is no relation to page meaning "sheet of paper" whatsoever.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.