simpatico, mutual understanding,
Tuning refers to manipulating an instrument -- by changing the tension of its strings or drumhead, for example -- in order that it produces specific pitches while being played.
The reason for tuning is twofold. First, we tune in order to play in tune with others; when a guitarist and trumpet player each play an A, they want their As to match. Second, we tune in order to facilitate particular music: if were playing traditional Chinese music, for example, we might tune our instrument to a Chinese scale.
In a casting, the Tuning Card refers to being in tune with others, to mutual understanding and simpatico. It can also refer to joining others, to getting "in tune" with them. Finally, the Tuning Card can indicate conforming to standards, as when we tune our instruments to set parameters.
To divine the meaning of this card in a casting, consider the Solfege Die it was drawn above or under.
Click here to learn more about the Compositional Cards as a whole.