block or concrete masonry unit
Also called cinder block, hollow block, concrete brick, concrete block, cement block, besser block, and breeze block – is a large rectangular block used in building construction. Block comes in many different shapes and sizes depending on your building requirements.
Block or Concrete Masonry Unit (CMU) can be used as a structural element in addition to being used as an architectural element. Ungrouted, partially grouted, and fully grouted walls are the different types of walls allowed. Reinforcement bars can be used both vertically and horizontally inside the CMU to strengthen the wall and results in better structural performance. The cells in which the rebar is placed must be grouted for the bars to bond to the wall. For this reason, high seismic zones typically only allow fully grouted walls in their building codes.