sev·enth / ˈsevən[unvoicedth]/ • ordinal number constituting number seven in a sequence; 7th: his seventh goal of the season | the seventh of June | he was the seventh of eight children. ∎  (a seventh/one seventh) each of seven equal parts into which something is or may be divided. ∎  the seventh finisher or position in a race or competition: he finished seventh in the tournament. ∎  seventhly (used to introduce a seventh point or reason). ∎  the seventh grade of a school. ∎  Mus. an interval spanning seven consecutive notes in a diatonic scale. ∎  Mus. the note that is higher by this interval than the tonic of a diatonic scale or root of a chord. ∎ Mus. a chord in which the seventh note of the scale forms an important component.PHRASES: in seventh heavensee heaven.DERIVATIVES: sev·enth·ly adv.

seventh in seventh heaven in a state of ecstasy; the term relates to the concept of seven heavens in late Jewish and Muslim theology.
Seventh-Day Adventist a member of a strict Protestant sect which preaches the imminent return of Christ to Earth (originally expecting the Second Coming in 1844) and observes Saturday as the sabbath.

seventh. Interval in melody or harmony when 2 notes, major or minor, are 7 steps apart (counting bottom and top notes). A up to G♯ is major seventh; A up to G♮ is minor seventh; A up to G♭ is diminished seventh.