1 Romanesque moulding carved to resemble a chain.
2 Piece of timber or metal built into a brick wall to increase its stability and cohesion, called chain-bond.
3 Bond course of stone with one or more cramps connecting each pair of stones.
4 Complete circlet formed of a chain, used to prevent a circular work of masonry from spreading, e.g. in the dome of St Paul's Cathedral, London (begun 1675).
5 Chain-tie used to connect the heads of piers, etc., while vaults and arches are constructed.
6 If used to tie in bulging brickwork, an anchor is fixed to the end of the chain or rod, visible on the outside of the wall.