Opus latericium

Opus latericium (Latin for "brick work") is an ancient Roman construction technique in which coarse-laid brickwork is used to face a core of opus caementicium.[1][2]

Example of opus latericium on a tomb of the ancient Appian Way in Rome.
A wall of the Domus Augustana in Rome

Opus latericium was the dominant form of wall construction in the Imperial era.[1] In the time of the architectural writer Vitruvius, opus latericium seems to have designated structures built using unfired mud bricks.[3]