A portable mill is a machine used to mill and grind materials on site. It's a tool frequently used in construction, agriculture, and manufacturing, as it can be easily transported from one location to another. There are several synonyms for the term portable mill, each of which sheds light on specific aspects of the machine. A portable sawmill is a type of portable mill that is used to saw wood into boards. A portable lathe is a type of portable mill that is used to shape metals. A mobile mill is another synonym for portable mill that emphasizes its ability to be carried around.