noun Surveying.
- (in plane-tabling) a straightedge having a telescopic sight or other means of sighting parallel to the straightedge.
- the entire upper part of a theodolite or transit, including the telescope, its supports, the level vials, the circle-reading device, and the spindle.
noun
- a surveying instrument used in plane-tabling for drawing lines of sight on a distant object and taking angular measurements
- the upper rotatable part of a theodolite, including the telescope and its attachments