A portico is a porch leading to the entrance of a building, or extended as a colonnade, with a roof structure over a walkway, supported by columns or enclosed by walls.
[2] The tetrastyle has four columns; it was commonly employed by the Greeks and the Etruscans for small structures such as public buildings and amphiprostyles.
Roman taste favoured narrow pseudoperipteral and amphiprostyle buildings with tall columns, raised on podiums for the added pomp and grandeur conferred by considerable height.
The best-known octastyle buildings surviving from antiquity are the Parthenon in Athens, built during the Age of Pericles (450–430 BCE), and the Pantheon in Rome (125 CE).
The destroyed Temple of Divus Augustus in Rome, the centre of the Augustan cult, is shown on Roman coins of the 2nd century CE as having been built in octastyle.