[tet.ra.chord] n [Gk tetrachordon, fr. neut. of tetrachordos of four strings, fr. tetra- + chorde string--more at yarn] (1603): a diatonic series of four tones with an interval of a perfect fourth between the first and last
TETRACHORD
Meaning of TETRACHORD in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012