Final answer:
A cylindrical support in classical architecture consisting of a capital, shaft, and usually a base is called a column. Columns are round, supporting elements in architecture that can be monolithic or built up of drums. On the other hand, pilasters are purely decorative rectangular columns that do not provide any support.
Step-by-step explanation:
A cylindrical support in classical architecture, consisting of a capital, shaft, and usually a base, is called a column. Columns are round, supporting elements in architecture. They can be monolithic, built up of drums, or have a base. The capital at the top of the column is the decorated part, which can be iconic or Corinthian in style.
The fluting is the vertical, indented lines or grooves that decorate the column. On the other hand, a pilaster is a rectangular column that projects partially from the wall to which it is attached. Pilasters are purely decorative and do not provide any support.