1. [n]  the musical interval between one note and another six notes away from it
2. [n]  a sixth part
3. [n]  position six in a countable series of things
4. [adj]  coming next after the fifth and just before the seventh in position

SIXTH is a 5 letter word that starts with S.

1. \Sixth\, a. [From Six: cf. AS. sixta, siexta.]
   1. First after the fifth; next in order after the fifth.
   
   2. Constituting or being one of six equal parts into which
      anything is divided.
   
   
   
   

2. \Sixth\, n.
   1. The quotient of a unit divided by six; one of six equal
      parts which form a whole.
   
   2. The next in order after the fifth.
   
   3. (Mus.) The interval embracing six diatonic degrees of the
      scale.