The Free On-line Dictionary of Computing (30 December 2018):

presentation layer
ISO 8822
ISO 8823
layer 6
X.216
X.226

    The second highest layer (layer 6) in the OSI
   seven layer model.  Performs functions such as text
   compression, code or format conversion to try to smooth out
   differences between hosts.  Allows incompatible processes in
   the application layer to communicate via the session
   layer.

   Documents: ITU Rec. X.226 (ISO 8823), ITU Rec. X.216 (ISO
   8822).

   (1996-07-20)