late Middle English (in the sense 'formed by cohesion, solidified'): from French concret or Latin concretus, past participle of concrescere 'grow together'. Early use was also as a grammatical term designating a quality belonging to a substance (usually expressed by an adjective such as white in white paper) as opposed to the quality itself (expressed by an abstract noun such as whiteness); later concrete came to be used to refer to nouns embodying attributes (e.g. fool, hero), as opposed to the attributes themselves (e.g. foolishness, heroism), and this is the basis of the modern use as the opposite of 'abstract'. The noun sense 'building material' dates from the mid 19th cent