Definition
A control on an altimeter or air data computer that lets the pilot enter the current local sea-level pressure setting (in inches of mercury or hectopascals) so the instrument displays the correct altitude for the surrounding atmospheric pressure.
Plain English
The knob or input that lets the pilot tell the altimeter what today's air pressure is, so the altitude reading is accurate.
Context Anchor
Seen on electronic flight displays, often as a BARO setting, when the pilot enters or updates the altimeter setting before and during flight.
Derivation
From 'barometer' (Greek baros, weight, plus metron, measure), an instrument for measuring air pressure. The 'correction' part refers to adjusting the altimeter so it accounts for the actual pressure on a given day, since pressure changes with weather.
Why Pilots Care
Correct barometric input prevents altitude errors that can exceed several hundred feet when flying between areas of differing pressure, directly affecting terrain clearance and assigned altitudes.
Intuition Check
Do not read “correction” as fixing a broken display. Here it means applying the current pressure setting so the altitude shown uses the correct pressure reference.
Example Sentence 1
Before takeoff, the pilot used the barometric correction device to set the altimeter to 30.05, matching the ATIS report.
Example Sentence 2
With the correct barometric setting entered, the EFD altitude readout aligned with the published field elevation during the approach.