cinder block
From Longman Dictionary of Contemporary Englishcinder blockˈcinder block noun [countable] American English TCBa large grey brick used to build houses and other buildings, made from cement and cinders SYN breeze-block British EnglishExamples from the Corpuscinder block• Three small houses, made of painted cinder block and aluminum, faced the hotel from across the street.• With notable exceptions, adobe slowly is giving way to cinder block and other inexpensive modern materials.• The room is maybe six feet square, with cinder block walls.