stoa

stoa, in Greek architecture, a freestanding colonnade or covered walkway; also, a long open building, its roof supported by one or more rows of columns parallel to the rear wall. The Stoa of Attalus at Athens is a prime example.

Stoae surrounded marketplaces and sanctuaries and formed places of business and public promenade. Rooms might back onto the colonnade, and a second story was sometimes added.