Plain English Meaning
How high the nose is held above the horizon during a climb. The pilot picks a specific nose-up angle and keeps it there so the airplane climbs steadily at the right speed.
Full Definition
The angle between the airplane's longitudinal axis and the horizon when the airplane is established in a climb, with the nose held above the horizon to produce a steady climb at a target airspeed and power setting.
Context Anchor
Used during takeoff, go-arounds, and normal climbs when the pilot sets the nose and then checks whether the airplane is climbing at the speed.