Abstract: A block having opposite first and second faces adapted for use in construon. The block comprises male and female assembly means for interlocking a plurality of the blocks. The block comprises at least one male assembly means protruding from the first face. Each of the male assembly means has a vertical section and two substantially horizontal sections arranged at both ends of the vertical section. The female assembly means is arranged on the second face of the block and has a substantially rectangular cross-section.A block for use in construction. The block comprises assembly means for interlocking a plurality of the blocks. The assembly means comprise first and second opposite faces provided with at least one male assembly means and one female assembly means. The male assembly means comprises a frangible section.The block covered by the invention offers the special advantage of permitting walls to be built by simple superimposition.