The Collaborative International Dictionary of English v.0.48:

Sao \Sa"o\, n. (Zool.)
   Any marine annelid of the genus Hyalinaecia, especially
   Hyalinaecia tubicola of Europe, which inhabits a
   transparent movable tube resembling a quill in color and
   texture.
   [1913 Webster]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SAO
       Server Activated Object


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SAO
       Session At Once (CD)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SAO
       Source Address Omitted [flag] (CATNIP)