A piezometer is a device used to measure pressure in a liquid, particularly in wells or boreholes. The Hales piezometer is a specific type of piezometer that was developed by Charles Ernest Hales in the early 20th century. While there may not be direct synonyms for the term "Hales piezometer", there are general terms used to describe similar devices. These include pressure gauge, manometer, depth gauge, and liquid pressure sensor. Each of these words refers to a device used to measure pressure in liquids, although they may differ in design and application. The Hales piezometer, however, is a notable contribution to the field of pressure measurement.