 | Machine Coated | | Paper which is coated one or two sides on a paper machine. |
| Machine Direction | | The direction of paper parallel to its forward movement on paper machine. |
| Machine Finish | | The finish applied on the paper machine. The finish is in a wove or laid design and is between Vellum and English finish in smoothness. The finish is commonly referred to as MF (machine finish). |
| Magenta | | One of the four primary colors for printing. One of the subtractive primaries the hue of which is used for one of the four color process inks. It reflects blue and red light and absorbs light. |
| Mandrel | | The core around which paper, fabric, or resin-impregnated fibrous glass is wound to form pipes or tubes. In extrusion, the central finger of a pipe or tubing die. |
| Mandrel Hold | | The ability to adhere to a curved or tight radius surface. Mandrel hold is the resistance to "Fflag" or "wing up". |
| Mass | | Sometimes used as another name for the adhesive. |
| Matrix | | Ladder, skeleton, waste. The face and adhesive layers of a sensitive construction surrounding a die-cut label which have been removed after die-cutting. |
| Matte Finish | | A dull finish. A deglossed surface. |
| MD | | Medium Durability |
| MDO | | Machine Direction Oriented |
| Mechanical Pulp | | In papermaking, groundwood pulp produced by mechanically grinding logs or wood chips. It is used mainly for newsprint and as an ingredient of base stock for lower grade publication papers. |
| Memory | | The property of a material that attempts to return to its original dimensions after being distorted. |
| Metallized Film | | A plastic or resinous film that has been coated on one side with a very thin layer of metal. |
| Migration | | The movement of one or more of the components of a pressure-sensitive adhesive to either a substrate or face material; the movement of one or more of the components of either or both the face material and the substrate into the adhesive and ink. |
| Mils | | Used in describing adhesive coat weights, thickness. The term means thousandths of an inch. |
| Minimum Application Temperature | | The lowest temperature at which an adhesive will function. |
| Moisture Content | | Percent moisture. The moisture present in a material, as determined by specified methods. |
| Moisture Resistant | | That property of a sheet which resists uptake or passage of moisture. Usually achieved by adding sizing. |
| Monomer | | The basic building block from which a polymer chain is made. Many monomer molecules are chemically joined to make up the polymer. |
| Mottle | | Non-uniform coloring, coating or printing of a face material. |