A surface gage, also known as a surface gauge, is a measuring tool often used in metalworking and woodworking industries to determine the flatness of surfaces. Some other synonyms for a surface gage include height gage or height gauge, which are used to measure the height of objects. Dial indicators and micrometers can also be used as a surface gage to measure features such as surface roughness or the depth of grooves. Other synonyms for a surface gage include marking gauge or scribing gauge, which are used to mark lines or circles on surfaces. Overall, there are various types of gauges that can be used for measuring surfaces, depending on the specific needs and requirements of a project.