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

write-through
write-thru

    (Or "write-thru") A cache architecture in
   which data is written to main memory at the same time as it is
   cached.

   Opposite of write-back.  See also buffered write-through,
   posted write-through, no-write allocation.

   (1996-06-12)