1) HS course 2) Attention-getting exclamation 3) Attention-grabber 4) High school subject 5) Hs subject 6) Past school course 7) Pulitzer prize subject 8) Schlesinger subj 9) School subject 10) Short high school subject 11) Sound for attention 12) Sound to attract attention 13) Trick taking card game 
expression used to attract attention
• (interj.) Hush; be silent; -- a signal for silence.
Hist interj. [ Confer Danish hys . .... Confer Hush , Whist .] Hush; be silent; -- a signal for silence. Milton. 
History
(a sibilant exclamation used to attract attention).