Plain English Meaning
The set of flight information shown on the main glass-cockpit screen in front of the pilot — attitude, airspeed, altitude, heading, climb or descent rate — all displayed together on one screen.
Full Definition
The collection of flight displays shown on the Primary Flight Display (PFD), including the attitude indicator, airspeed tape, altimeter, vertical speed indicator, heading indicator, and slip/skid indication, all presented electronically on a single screen in place of traditional mechanical instruments.