140/81, the septimal semidiminished seventh or septimal inframinor seventh is a 7-limit interseptimal ratio of about 947 cents. It is flat of a minor seventh 16/9 by a septimal quartertone 36/35, flat of a subminor seventh 7/4 by a syntonic comma 81/80, and sharp of a supermajor sixth 12/7 by a sensamagic comma 245/243.
It is also sharp of a major sixth 5/3 by a subminor second 28/27. For this fact it is useful in the Canovian chord and provides the function of a voice leading down to the major sixth. The canou temperament targets this progression and uses it as one of the generators.