What is the meaning of 平調?

to transfer to a different position of the same rank

calm, ordinary, or usual condition/tone.

A tuning method for the Chinese sanxian. Corresponds to the honchōshi (standard tuning) of the shamisen. The strings are tuned to the pitches gō (合), sui (四), and ryū (六).

One of the twelve pitches (jūniritsu) in traditional Japanese music. Two semitones higher than the fundamental pitch ichikotsu (壱越). It corresponds to the pitch taicù (太簇) in traditional Chinese music and the pitch E in Western music.

The hyōjō mode. One of the six basic modes (rokuchōshi) in gagaku (Japanese court music), utilizing the pitch E as its fundamental tonic.

Source: wiktionary.org