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

session layer
ISO 8326
ISO 8327
layer 5
X.215
X.225

    The third highest protocol layer (layer 5) in the
OSI
   seven layer model.  The session layer uses the transport
   layer to establish a connection between processes on
   different hosts.  It handles security and creation of the
   session.  It is used by the presentation layer.

   Documents: ITU Rec. X.225 (ISO 8327), ITU Rec. X.215 (ISO
   8326).

   [Examples?]

   (1997-12-07)