“Required open space” means a portion of the area of a lot or building site, other than required yards, which area is required by this title, as set forth in the different classifications contained herein, to be maintained between buildings, between wings of a building, and between buildings and any portion of a property boundary line not contiguous to a required front or side yard. Such open spaces, as in the case of required yards, are required to be free and clear of buildings and structures and to remain open and unobstructed from the ground to the sky. (Ord. 2020 § 2, 1994; Ord. 190 Art. IV § 415, 1964)