Tetrachords: Phrygian (1 b2 b3 4)

Traditionally, a tetrachord is a series of four tones filling in the interval of a perfect fourth. In modern usage a tetrachord is any four-note segment of a scale or tone row including the augmented fourth (+4). The term tetrachord derives from ancient Greek music theory, it literally means four strings.

C, C7, Cmaj7, C+7

Chords with a minor third in them can use a tetrachord with a minor third in them: Examples: Cm, Cm7, Cmin-maj7, Cm6