Plain English Meaning
A written, signed note from a flight instructor in your logbook that says you have been trained to do something specific and are cleared to do it.
Full Definition
A signed and dated entry made by an authorized flight instructor in a pilot's logbook (or other approved record) certifying that the pilot has received specific training, met defined proficiency standards, or is authorized to perform a particular operation under the regulations.
Context Anchor
Seen in pilot logbooks, training records, and FAA training requirements, especially when a student or sport pilot needs documented approval for a privilege.
Derivation
From the Latin 'in-' (on) and 'dorsum' (back) -- literally 'on the back.' Originally it meant signing the back of a document to confirm or approve it. In aviation, the instructor's signature serves the same purpose: a formal stamp of approval recorded in writing.
Why Pilots Care
Without the correct endorsement a pilot is not legally authorized to fly the aircraft or exercise the privilege, which can ground them or create regulatory violations.
Intuition Check
Do not read endorsement here as a casual recommendation or public support. In FAA use, it means a specific written approval or confirmation placed in an official training record.
Example Sentence 1
Before her first solo, the student received a logbook endorsement from her instructor certifying she was trained and proficient to fly the airplane alone.
Example Sentence 2
The pilot needed a new endorsement before acting as pilot in command of the different light-sport model.