wall

   [WPI]

   1.  An indication of confusion, usually spoken with a quizzical tone:
   "Wall??"

   2. A request for further explication. Compare {octal forty}.

   3.  [Unix,  from  `write  all']  v.  To  send  a  message to everyone
   currently logged in, esp. with the wall(8) utility.

   It  is said that sense 1 came from the idiom `like talking to a blank
   wall'.  It  was  originally  used  in situations where, after you had
   carefully  answered a question, the questioner stared at you blankly,
   clearly  having understood nothing that was explained. You would then
   throw  out  a "Hello, wall?" to elicit some sort of response from the
   questioner.   Later,   confused  questioners  began  voicing  "Wall?"
   themselves.

[glossary]
[Reference(s) to this entry by made by: {hello, wall!}{octal forty}{ques}]