pilaster
The representation in relief of a column against a wall. The pilaster is sometimes considered as the visible part of a square column built into the wall. Pilasters are necessarily ornamental. They have a quasi-structural function, however, when acting as responds, i.e. as the thickening of a wall opposite a column whose entablature carries over to the wall. Photo from York, Pennsylvania, 2019. (Summerson, 1963)