- noun a line along which an aircraft is known to be at a particular time, usually by taking a VOR bearing.
- In navigation, a line of bearing to a reference or other known point, along which a vessel considered to be located. Such a line may be determined for instance, through the use of radar, loran, ultrasound, landmarks, GPS, and so on. More than one position line may be utilized for a fix. Also called line of position.