theodolite

Definition

A surveying instrument, consisting of a small mounted telescope, used to measure horizontal and vertical angles.

Etymology

From New Latin theodolitus (1571), perhaps containing Ancient Greek θέᾱ (théā, “sight, view”) and Arabic العِضَادَة (al-ʕiḍāda, “astrolabe, alidade”); if so, doublet of alidade.

Example Sentences

• "I drew outlines (according to my usual custom) of all the hills on the horizon before us, and took angles on them with the theodolite."
• "The height of those mountains was from five to seven thousand feet above our level, by angular measurement with a theodolite."
• "It was a lieutenant and a couple of privates of the 8th Hussars, with a stand like a theodolite, which the artilleryman told me was a heliograph."