The Collaborative International Dictionary of English v.0.48:

Sargo \Sar"go\, n. [Sp. sargo, L. sargus a kind of fish.]
   (Zool.)
   Any one of several species of sparoid fishes belonging to
   Sargus, Pomadasys, and related genera; -- called also
   sar, and saragu.
   [1913 Webster]

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

SAR
       Segmentation And Reassembly


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

SAR
       Store Address Register (IC)


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

segmentation
reassembly
SAR
segmentation and reassembly

    (Or "segmentation and reassembly", SAR) Breaking
   an arbitrary size packet into smaller pieces at the
   transmitter.  This may be necessary because of restrictions in
   the communications channel or to reduce latency.  The pieces
   are joined back together in the right order at the receiver
   ("reassembly").  Segmentation may be performed by a router
   when routing a packet to a network with a smaller maximum
   packet size.

   The term "segmentation" is used in ATM, in TCP/IP, it is
   called "fragmentation" an is performed at the IP layer
   before the "fragments" are passed to the transport layer.

   See for example ATM forum UNI 4.0 specification.

   [Better reasons?]

   (1999-06-14)