A luminous trace left in the sky by the passage of a large meteor.

A line of rock fragments that were picked up by glacial ice at a localized outcropping and left scattered along a fairly well-defined tract during the movement of a glacier.

One of the lines left on a photographic plate during prolonged exposure to starlight if the motion of the plate was not synchronized with the apparent motion of the sky.

1. In bombing, the line between the point of impact of the bomb and a point on the ground directly beneath the aircraft at the moment of impact, assuming that the aircraft stays on course after release of the bomb and maintains a constant speed.

2. Rear part of a gun carriage which connects the piece with a limber or tractor.