questa pagina in italiano

Columns that you find in the list are either honorary or commemorative. Sometime they have an internal snail type staircase, to get to the top of the column itself. The three classical types are: 

• Doric: it is the simplest of the orders, characterized by short, faceted, heavy columns with plain, round capitals (tops) and no base. With only four to eight diameters in height, the columns are the most squat of all orders. The shaft of the Doric order is channeled with 20 flutes. The capital consists of a necking which is of a simple form. The echinus is convex and the abacus is square.

• ionic: it is distinguished by slender, fluted pillars with a large base and two opposed volutes (also called scrolls) in the echinus of the capital. The echinus itself is decorated with an egg-and-dart motif. The Ionic shaft comes with four more flutes than the Doric counterpart (totalling 24). The Ionic base has two convex moldings called tori which are separated by a scotia.

• Corinthian: the most ornate of the Greek orders, characterized by a slender fluted column having an ornate capital decorated with two rows of acanthus leaves and four scrolls. It is commonly regarded as the most elegant of the three orders.

Courtyards

The courtyard ( porticus in Latin) is an open gallery, usually outside and at the ground floor of a building. It could be used as a repair for the whether or only for a decorative purpose. They usually consisted in a long columns series bearing  a trabeation; this is why they are also called columnate. When the columnate was in front of a building, covering the main gate, is then a courtyard in strict sense while, if enclosed an open space, is better to call it a peristiulium. If the courtyard has four sides, it is then a quadriporticus.

The porticus was famous also before the greek civilization but it was at that time, and after with the Romans, that it had the greatest development (the Greek stoà) where it was used for civil or religious purposes.

Cryptoportici

In Roman architecture a cryproporticus (from greek crypta and  Latin porticus) was a vaulted aisle or a passway. The cryptoporticus is usually at ground level or half in the ground, and under a structure such as a forum or a domus, a Roman villa. It is often vaulted and lightened by openings called "wolf mouths".

from Wikipedia website