Crescent is a common adjective used to indicate a street or terrace of houses forming an arc.
What is the most appropriate way to call or describe this kind of road in Italian?
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According to this source,
Strada a mezzaluna
I've never heard of it. It's not a common expression at all, although these streets exist.
Another possibility is a locuzione with "arco" or "semicerchio":
La strada fa/disegna un arco
If it is bent like a horseshoe:
Ferro di cavallo
In particular, a "hairpin" on a mountain road: