Aqueous coating: Coating applied to pages after they’ve been printed that helps prevent the ink from rubbing off and that can give the paper a matte or gloss finish.

Basis weight: The weight, in pounds, of a ream (500 sheets) of paper cut to the basic size for that particular paper grade; also called ream weight.
Bleed-through: When an image from one side of a sheet of paper is visible on the other, often due to a lack of opacity in the paper; also called show-through.

Brightness: The percentage of light that is reflected from a sheet of paper; the brighter the paper, the greater the contrast in the images.
Calender: To press paper between rollers during the manufacturing process in order to create a smoother product.

Coated freesheet: Coated paper containing no more than 10% groundwood pulp; the low groundwood-pulp content makes it whiter, heavier, more durable, and more expensive than groundwood papers.

Coated groundwood: Coated paper containing 10%-75% groundwood pulp

Coated paper: Paper whose surface has been treated with a mix of binders (such as starch and latex) and pigment to improve its quality.

CWT: Abbreviation for hundredweight.

Density: A paper’s weight in comparison to its bulk.

Free sheet: High-quality paper that’s free of or almost free of groundwood pulp.

Grade: Quality of a paper based on its contents and method of manufacturing.

Groundwood pulp: A mechanically produced wood pulp used to make inexpensive grades of paper; also called mechanical pulp.

Mill brand: A paper’s brand name.

Opacity: The amount of bleed-through of a piece of paper.

Paper merchant: Middleman who buys paper from the manufacturer and sells it to the buyer; a merchant typically works with multiple manufacturers.

Postconsumer waste paper: Paper that was disposed after reaching the end user, such as discarded newspapers and stationery.

Preconsumer waste paper: Paper that was disposed of before reaching the end user—for instance, the trimmed ends of a catalog before it is mailed.

Self-cover: Use of the same type of paper for the cover as for the inside pages.

Signature: A folded sheet of paper that consists of a set number of pages. All signatures are multiples of four, with 16-page signatures the most common; also called forms.

Supercalendered (SC) paper: Paper that is calendered between alternating chrome and fiber rollers, making it smoother and glossier than calendered paper.

Virgin paper: Paper with no recycled content.