Plain English Meaning

A setting on the autopilot that lets the airplane follow the invisible sloped beam coming up from the runway, so it descends at the right angle for landing without the pilot flying it by hand.

Full Definition

An autopilot mode that captures and tracks the vertical guidance signal of an Instrument Landing System (ILS), holding the aircraft on the published descent path to the runway. Once armed and the glideslope signal is received, the autopilot transitions from its previous vertical mode and adjusts pitch to keep the aircraft on the glideslope until disengagement at minimums or .