the musical interval between one note and another three notes away from it; "a simple harmony written in major thirds"
following the second position in an ordering or series; "a distant third"; "he answered the first question willingly, the second reluctantly, and the third with resentment"
coming next after the second and just before the fourth in position
in the third place; "third we must consider unemployment"
an informant who exposes wrongdoing within an organization in the hope of stopping it; "the law gives little protection to whistleblowers who feel the public has a right to know what is going on"; "the whistleblower was fired for exposing the conditions in mental hospitals"
the musical interval between one note and another four notes away from it
following the third position; number four in a countable series
coming next after the third and just before the fifth in position or time or degree or magnitude; "the quaternary period of geologic time extends from the end of the tertiary period to the present"