The A4 is part of the ISO "A Series," where A0, the first dimension, equals almost one square meter (841x1189mm = 999,949 square mm). Starting with A1, each size is one half the square surface area of the previous size while maintaining the same aspect ratio.
Printing and writing papers are paper grades used for newspapers, magazines, catalogs, books, notebooks, commercial printing, business forms, stationeries, copying and digital printing. About 1/3 of the total pulp and paper marked (in 2000) is printing and writing papers. ... Coated Freesheet Paper. Coated Mechanical Paper.
paper specially prepared for the writing of advertising copy, newspaper copy, etc., usually having guidelines to indicate margins and the number of spaces per line.