Arch 3 : An arch is an arrangement of blocks (voussoirs) disposed in the line of a curve, for distributing a superimposed load, the blocks supporting one another by mutual pressure. Many arches are, however, only nominal arches
H. J. Porter (Chairman - Technical Committee), Dictionary of Fire Technology, The Institution of Fire Engineers, The Victory Press (Leicester) Ltd. 1979 UK. (Fr Tech - Brit) {81}