Theodolite is an instrument used in surveying and engineering to MEASURE angles in the horizontal and vertical planes. It is also known as a TRANSIT or surveyor's TRANSIT. The term 'theodolite' comes from the Greek words for 'GOD' and 'MEASURE'. The instrument is composed of a telescope mounted on a tripod, with a graduated circle that can be rotated to MEASURE angles in the horizontal and vertical planes. Theodolites are used to MEASURE distances, angles, and elevations in order to create accurate maps and surveys. The word 'TRANSIT' is derived from the Latin word for 'to pass over', which is fitting since theodolites are used to MEASURE angles and distances in order to create accurate maps and surveys.