Stoas, also spelled as stoa, refer to a type of ancient Greek portico or covered walkway. When looking for synonym options for this word, one can consider terms such as colonnaded porch, arcade, peristyle, or ambulatory. Each of these words implies a structure or pathway with columns or arches that provide shelter from weather elements. In more modern contexts, one could use terms like covered walkway, veranda, or portico as equivalents to stoas. Ultimately, the choice of synonym will depend on the specific context and desired connotations of the term.