A transit declinometer is a tool used to measure the angle between magnetic north and true north. It is a vital instrument for navigation and orientation. However, there are various synonyms for the transit declinometer that may be used interchangeably. Some of these include magnetic declination instrument, compass declination, compass needle, and azimuth compass. They all refer to different variations of the same instrument that are designed to measure different aspects of navigation. Regardless of the synonyms used, the transit declinometer remains a crucial device for navigating across the globe. It helps sailors, pilots, hikers, and other explorers to accurately locate their position and follow their desired course.