solid concrete block

solid masonry unit

solid-core door 1.(US) A masonry unit whose net cross-sectional area in every plane parallel to the bearing surface is 75% or more of its gross cross-sectional area measured in the same plane. 2. (Brit.) A solid masonry unit having small holes, less than¾ in. (2 cm) wide or less than ¾ sq in. (5 sq cm) in area, passing through it but not exceeding 25% of its volume, or having frogs that do not exceed 20% of its volume. Up to three larger holes, not exceeding 5 sq. in. (32.5 sq cm) each, may be incorporated as aids to handling, within the total of 25%.