processed paper; coated paper
General term for paper that has undergone additional treatment, such as coating, laminating, or chemical processing, to give it specific properties.
This brochure uses glossy coated paper.
Processed paper is treated to improve water resistance and strength.
コート紙 is a specific type of coated paper, often used for printing; 加工紙 is a broader category that includes coated and other processed papers.
Compound of 加工 (processing) and 紙 (paper). The term is straightforward and modern, with no obscure historical derivation.