What contraction is used to denote 5/8 to 7/8 of sky covered by clouds?

The contraction used to denote 5/8 to 7/8 of the sky covered by clouds is "BKN," which stands for "broken." In meteorological terminology, "broken" indicates that a significant portion of the sky is obscured by clouds—specifically, when the coverage is between 5 and 7 eighths. This term helps pilots and meteorologists understand the level of cloud cover that might impact visibility and flight operations.

"Scattered," which denotes fewer clouds (1/8 to 4/8 of the sky covered), would not apply in this case since it represents a lesser degree of coverage. "Overcast" signifies that more than 7/8 of the sky is covered, which exceeds the range stated in the question. "Clear" indicates a complete absence of significant cloud cover, making it irrelevant for the specified cloud coverage of 5/8 to 7/8.