This document specifies terms and definitions for non-destructive testing by the technique of metal magnetic memory (MMM) as well as general requirements for application of this technique of the magnetic testing method. The terms specified in this document are mandatory for application in all types of documentation and literature of non-destructive testing, using the metal magnetic memory technique. This NDT technique has the following objectives: – Determination of the heterogeneity of the magneto-mechanical state of ferromagnetic objects, detection of defect concentration and boundaries of metal microstructure heterogeneity. – Determination of locations with magnetic stray field aberrations for further microstructural analysis and/or non-destructive testing and evaluation. – Early diagnostics of fatigue damage of the inspected object and evaluation of its structural life time. – Quick sorting of new and used inspection objects by their magnetic heterogeneity for further testing. – Efficiency improvement of non-destructive testing by combining metal magnetic memory testing with other NDT methods or techniques (ultrasonic testing, X-ray, etc.) by fast detection of the most probable defect locations. – Quality control of welded joints of various types and their embodiment (including contact and spot welding); see Part 2 of this standard for details of this application.