Stoa

A stoa (; plural, stoas,"stoa", Oxford English Dictionary, 2nd Ed., 1989 stoai, or stoae ), in ancient Greek architecture, is a covered walkway or portico, commonly for public use. Early stoas were open at the entrance with columns, usually of the Doric order, lining the side of the building; they created a safe, enveloping, protective atmosphere.
This, an "open-fronted shelter with a lean-to roof", is the meaning in modern usage, but in fact the ancient Greeks "made... meer