0 a piece of string with a weight attached to one end, used either to test if something vertical, such as a wall, is exactly straight, or to find the depth of water -- （测垂直面或水深的）铅垂线，重锤线
The astrologer's instruments ("horologium" and "palm") are a plumb line and sighting instrument.
It involved the use of a bar with a plumb line, attached to a wooden handle.
A plumb line dropped from the tower revealed that the concrete block had settled during the storm, giving the lighthouse a pronounced shoreward list.
It even gave instructions on how to obtain measurements using the plumb line.
It is derived by deducting normal heights from the normal plumb line.
There were instances of bricks, plumb lines and so on being thrown from bridges, and of tankers being forced on to the hard shoulder.
If the notches corresponding to the plumb lines matched on both sides, it showed that the beam was level.
To keep the shafts to the correct alignment, plumb lines were used.
