EMC means nothing more than "an electronic or electrical product shall work as intended in its environment. The electronic or electrical product shall not generate electromagnetic disturbances, which may influence other products". In other words, EMC deals with problems of noise emission as well as noise immunity of electronic and electrical products and systems. Electromagnetic disturbances occur as conducted interference as well as radiated emissions and immunity problems.
Generally EMC, Electro Magnetic Compatibility, should really not be difficult to understand, but as you know, the devil is in the details. Let us explain the topic in a little bit more details. For those of you who are EMC-experts, we hope you excuse us for making some "non-scientific" simplifications. The word EMC does not include the influence of electromagnetic waves (either desired or undesired) on biological systems. This is a much larger field and is covered by the expression "EMCE" ("E" is for environmental), which is not the topic here and is also not the field in which EM TEST works.