Blind arch Wikipedia
A blind arch is an arch found in the wall of a building which has been infilled with solid construction so it cannot serve as a passageway, door, or window. The term is most often associated with masonry wall construction, but is also found (or simulated) in other types of construction such as light frame construction. Some blind arches were originally built as open arches and infilled at a later date. Others were originally built with solid infill as intentional stylistic elements.