Abrasion resistance – the level at which paper can withstand continuous scuffing or rubbing.

Absorption – the properties within paper that cause it to absorb liquids (inks, water, etc.) which come in contact with it.

Accordion fold – a binding term describing a method of folding paper. When unfolded it looks like the folds of an accordion.

Acetate proof – a transparent, acetate printing proof used to reproduce anticipated print colors on a transparent acetate sheet.

Acetate pulp – a manufactured fiber in which the fiber–forming substance is called cellulose acetate. Acetate is manufactured by treating purified cellulose refined from cotton linters and/or wood pulp with acetic anhydride in the presence of a catalyst.

Acid free – paper made in a neutral pH system, usually buffered with calcium carbonate. This increases the longevity of the paper.

Acidity – degree of acid found in paper measured by the pH level. From 0 to 7 is classified acidic versus 7 to 14, which is classified as alkaline.

Adhesives – any substance that can hold materials together in a functional manner by surface attachment that resists separation. “Adhesive” as a general term includes cement, mucilage, glue, and paste—terms that are often used interchangeably for any organic material that forms an adhesive bond.

Against the grain – a right angle to which the fiber direction of a piece of paper lies. Folding with, not against, the grain is recommended.

Aging – irreversible alteration, generally deterioration, of the characteristics of paper or board produced in the course of time such as folding endurance, color etc. It is commonly associated with the diminishing of brightness of pulp and paper with age or the developing of a yellow color.

Alcohol / Alcohol substitutes – liquids added to the fountain solution of a printing press to reduce the surface tension of water.

Alkaline papermaking – alkaline papermaking refers to the formation of paper sheets from fiber slurries having a pH generally in the range of 7 to 9. Alkaline paper sheets typically contain some form of calcium carbonate filler.

Aluminum plate – a metal press plate used for moderate to long runs in offset lithography to carry an image.

Anti–offset spray – in printing, a material (usually dry starch particles) sprayed on to the wet ink film surface to prevent set–off.

Antique finish – a paper finish, usually used in book and cover papers, that has a tactile surface. Usually used in natural white or cream white colors.

Apparent density – weight (mass) per unit volume of a sheet of paper obtained by dividing the basis weight (or grammage) by caliper (thickness).

Aqueous coatings – aqueous coating is a clear, fast–drying water–based coating that is used to protect printed pieces. It provides a high–gloss or matte surface that deters dirt and fingerprints. Aqueous coating improves the durability of postcards and other printed pieces as they go through the mail and protects business cards as they are carried in peoples' wallets. It also looks beautiful on brochures, catalog covers, and presentation folders. Aqueous coatings provide more substantial scuff–resistance than varnishes. Aqueous is typically applied to the entire printed piece, usually by the last unit on a printing press. Due to its water base, aqueous coating is more environmentally friendly than varnish or UV coatings.

Archival – acid free or neutral paper that includes a minimum of 2% calcium carbonate to increase the longevity of the paper.

Artwork – original materials, including the illustrations, lettering, charts, color blocks, etc. which are to be reproduced in a printed piece.

Ascenders – the tops of lower–case letters such as: b,d,h and t.