1. [n]  a quick run
2. [v]  run very fast, usually for a short distance

SPRINT is a 6 letter word that starts with S.

1. \Sprint\, v. i. [imp. & p. p. {Sprinted}; p. pr. & vb. n.
   {Sprinting}.] [Cf. {Sprunt}.]
   To run very rapidly; to run at full speed.
   
         A runner [in a quarter-mile race] should be able to
         sprint the whole way.                    --Encyc. Brit.
   
   

2. \Sprint\, n.
   The act of sprinting; a run of a short distance at full
   speed.
   
   {Sprint race}, a foot race at the highest running speed; --
      usually limited to distance under a quarter of a mile.
   
   

List processing language involving stack operations. "SPRINT - A Direct Approach to List Processing Languages", C.A. Kapps, Proc SJCC 30 (1967). Sammet 1969, p 462.