Definition
A turn flown with a small angle of bank, generally less than about 20 degrees, producing a slow rate of turn and a gentle change in heading.
Plain English
A turn where the wings are tilted only a little, so the airplane changes direction slowly and smoothly.
Context Anchor
Seen in ground-reference maneuvers such as the rectangular course, where the pilot changes the amount of bank to account for wind and groundspeed.
Derivation
Shallow' comes from Old English meaning 'not deep.' Applied to a turn, it describes a bank angle that is small rather than steep — the wings are only slightly tilted from level.
Why Pilots Care
Using the correct shallow bank lets the pilot correct for wind drift on each leg without losing sight of the ground references or adding unnecessary load.
Grounding Statement
Picture the wings tilted only a little from level while the airplane slowly curves around the corner of the rectangular course.
Intuition Check
Shallow does not mean careless or incomplete here. It means a small amount of sideways tilt in the turn.
Example Sentence 1
On the downwind leg of the rectangular course, the pilot rolled into a steep bank, then transitioned to a shallow-banked turn as the airplane turned into the wind.
Example Sentence 2
A shallow-banked turn on the base leg let the airplane roll out exactly on the extended centerline without overshooting the final approach path.