Stoas  are unique to Ancient Greek architecture. They were covered walkways or porticos, mainly for public use. Early stoas were open at the entrance with columns, usually of the Doric order, lining the side of the building. They were well suited for the mild climate of Greece.
Later buildings of this style had two floors. A roof supported the inner colonnades. On the second floor were shops or offices. They followed Ionic architecture. Merchants could sell their goods. Artists could display their artwork. Religious gatherings could take place. Stoas usually surrounded the marketplaces of large cities.
- "stoa", Oxford English Dictionary, 2nd Ed., 1989
- Michael Gagarin; Elaine Fantham, The Oxford Encyclopedia of Ancient Greece and Rome, Vol 5 (Oxford: Oxford University Press, 2010), p. 387