English Dictionary

triangulation pillar

noun

(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.

I spotted a triangulation pillar on top of the hill.

意味（1）

(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.