A4
From Longman Dictionary of Contemporary EnglishA4A4 /ˌeɪ ˈfɔː◂ $ -ˈfɔːr◂/ noun [uncountable] a standard size of paper, used in Europe and Japan. A4 paper measures 210 x 297 millimetres → A3, A5Examples from the CorpusA4• Two A4 models are available: the 1. 8T and the A4 2. 8.From Longman Business DictionaryA4A4 noun [uncountable]OFFICE a standard paper size used in Europe, measuring 210297 mmA4 paper