מָבוֹי שֶׁיֵּשׁ לוֹ שְׁלֹשָׁה כְּתָלִים הוּא הַנִּקְרָא מָבוֹי סָתוּם. וּמָבוֹי שֶׁיֵּשׁ לוֹ שְׁנֵי כְּתָלִים בִּלְבַד זֶה כְּנֶגֶד זֶה וְהָעָם נִכְנָסִין בְּרוּחַ זוֹ וְיוֹצְאִין בְּשֶׁכְּנֶגְדָהּ הוּא הַנִּקְרָא מָבוֹי הַמְפֻלָּשׁ:
1 An alley that has three walls is called a closed alley. But an alley that only has two walls that are across from each other - and the people enter from this direction and exit in the one across from it - is called an open alley.
