Source : Webster's Revised Unabridged Dictionary (1913)

Counterman \Coun"ter*man\ (koun"t[~e]r*man), n.; pl.
   {Countermen} (-men).
   A man who attends at the counter of a shop to sell goods.
   [Eng.]

Source : WordNet®

counterman
     n : someone who attends a counter (as in a diner) [syn: {counterperson},
          {counterwoman}]