Mg and Metallic element

Mg noun - A light silver-white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spinel and olivine).

Metallic element and mg are semantically related. In some cases you can use "Metallic element" instead a noun "Mg".

Metallic element noun - Any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc..

Mg and metallic element are semantically related. Sometimes you can replace term "Mg" with "Metallic element", this terms are similar.