From Longman Dictionary of Contemporary Englishplain flourˌplain ˈflour noun [uncountable] British EnglishDF flour that contains no baking powder → self-raising flour
Examples from the Corpus
plain flour• Appendix B Recipes for play dough Mix plain flour and water with a little salt.• Thicken towards the end of cooking if necessary with plain flour mixed with a little water and a few drops of bottled gravy browning. 