Plain English Meaning
The upright frame on the side of a door opening. On an airplane, it's the vertical part of the doorway you check during walk-around for damage, loose fittings, or blocked vents.
Full Definition
The vertical structural member of an aircraft door frame, forming part of the cabin opening. On many light airplanes the doorpost contains a small static port or vent and may carry placards, hinges, or latching hardware that should be inspected during preflight.
Context Anchor
Seen during a visual preflight inspection around cabin, cargo, or baggage doors, especially when checking for cracks, looseness, or damage near the door opening.