triangulation pillar
English
Noun
triangulation pillar (plural triangulation pillars)
- (UK) A concrete pillar used by the Ordnance Survey as a point for taking theodolite measurements, used in determining the exact shape of the country in a mid-20th-century retriangulation project.
Synonyms
- triangulation station
- trigpoint
- trig pillar
- trigonometrical station
Further reading
triangulation pillar on Wikipedia.Wikipedia