septenary /sɛpˈtiːnəɹi/adjective 3noun 3forms 1 adjective3 •Consisting of or containing seven. •Lasting seven years; continuing seven years.Septenary penance. — 1655 •Of seventh rank or order. noun3 •A group of seven things. •A period of seven years.This idea was based on the doctrine that a man's body changed its character every seven years and that his life was thus made up of ‘septenaries’. — 1971 •The seven notes of the diatonic scale. formsseptenaries