The Greeks designed three classic forms of columns for their largest buildings. These were easily identified by the designs on their capitals (the top part upon which the weight of the roof rests). These were the Doric, Ionic and Corinthian styles.
Doric Column is the simplest design with little or no embellishment on the capital. The colums were also wider at the bottom and most often is without a elaborate base, resting directly on the support floor.
Ionic Columns have the distinct scroll design, or volute as the Greek would call it, at the capital.
The Corinthian Column is the most elaborate of the three. Classic Corinthian columns are slender, usually fluted (vertically grooved), decorated with a capital of leaves (most often the acanthus) and scrolls.