Definition:
Paper that does not have any kind of coating such as clay or latex applied to it is uncoated paper. Uncoated paper is available in many different finishes, colors, and weights.
Just as your clothes will absorb more water when you aren't wearing a coat, uncoated paper is more absorbent than coated paper. Thin uncoated paper may be more prone to bleed-through than thicker papers or coated papers.
