A push exercise involves a pushing motion. These exercises generally involve the chest, triceps, shoulders, quads, and calves. A pull exercise involves a pulling motion. These exercises generally involve the back, biceps, traps, and hamstrings.
Push exercises- Bench Press, Shoulder Press, Pushdowns, Leg Press, etc.
Pull exercises- Row, Barbell Curl, Deadlifts, Shrugs, etc.