There are various synonyms for the word "altigraph," which refers to a mechanism or device used for measuring altitude. Some of the common synonyms for the word include altimeter, altitude meter, elevation gauge, height meter, and height gauge. These words are used interchangeably to describe equipment that measures the height or altitude of an object or location, such as an aircraft, mountain, or building. The purpose of using these synonyms is to provide alternative ways of describing the same instrument or technology, helping readers to understand and communicate more effectively about altitude measurement.