Qu'est-ce qu'un concrete? Qu'est-ce qu'un concrete? Of or relating to an actual, specific thing or instance; particular: had the concrete evidence needed to convict. Existing in reality or in real experience; perceptible by the senses; real: concrete objects such as trees. Formed by the coalescence of separate particles or parts into one mass; solid. Made of hard, strong, conglomerate construction material.A hard, strong construction material consisting of sand, conglomerate gravel, pebbles, broken stone, or slag in a mortar or cement matrix.A mass formed by the coalescence of particles.To build, treat, or cover with hard, strong conglomerate construction material.To form into a mass by coalescence or cohesion of particles or parts.To harden; solidify.