- an instrument for measuring the intensity of a magnetic field, especially the earth’s magnetic field.
- an instrument for detecting the presence of ferrous or magnetic materials, especially one used to detect concealed weapons at airports.
- any instrument for measuring the intensity or direction of a magnetic field, esp the earth’s field
- An instrument for measuring the magnitude and direction of a magnetic field. Magnetometers are often used in archaeological and geological investigations to determine the intensity and direction of the Earth’s magnetic field at various times in the past by examining the strength and direction of magnetization of ferromagnetic materials in different geological strata. See also magnetic reversal.