A file of saved abbrev definitions is actually a file of Lisp code.
The abbrevs are saved in the form of a Lisp program to define the same
abbrev tables with the same contents. Therefore, you can load the file
with load (see How Programs Do Loading). However, the
function quietly-read-abbrev-file is provided as a more
convenient interface. Emacs automatically calls this function at
startup.
User-level facilities such as save-some-buffers can save
abbrevs in a file automatically, under the control of variables
described here.
This is the default file name for reading and saving abbrevs. By default, Emacs will look for ~/.emacs.d/abbrev_defs, and, if not found, for ~/.abbrev_defs; if neither file exists, Emacs will create ~/.emacs.d/abbrev_defs.
This function reads abbrev definitions from a file named filename,
previously written with write-abbrev-file. If filename is
omitted or nil, the file specified in abbrev-file-name is
used.
As the name implies, this function does not display any messages.
A non-nil value for save-abbrevs means that Emacs should
offer to save abbrevs (if any have changed) when files are saved. If
the value is silently, Emacs saves the abbrevs without asking
the user. abbrev-file-name specifies the file to save the
abbrevs in. The default value is t.
This variable is set non-nil by defining or altering any
abbrevs (except system abbrevs). This serves as a flag for various
Emacs commands to offer to save your abbrevs.
Save all abbrev definitions (except system abbrevs), for all abbrev
tables listed in abbrev-table-name-list, in the file
filename, in the form of a Lisp program that when loaded will
define the same abbrevs. Tables that do not have any abbrevs to save
are omitted. If filename is nil or omitted,
abbrev-file-name is used. This function returns nil.