Keywords: whistle
Sign Definition
As a Noun
                                            1.  A small metal tube which you blow in order to produce a loud sound and attract someone's attention. It is often used by umpires and referees. English = whistle.
                                          
                                          
                                        As a Verb or Adjective
                                            1.  To blow on a whistle, to whistle.
                                          
                                          
                                         
                  
                      