Passing chord

In music, a passing chord is a nondiatonic chord that connects, or passes between, the notes of two diatonic chords. "Any chord that moves between one diatonic chord and another one nearby may be loosely termed a passing chord. A diatonic passing chord may be inserted into a pre-existing progression that moves by a major or minor third in order to create more movement." "'Inbetween chords' that help you get from one chord to another are called passing chords."