On Wednesday, 18 Dec 2019 at 11:02, Sharon Kimble wrote:
> I've tried using a symlink to the file held in another directory, but
> when I restarted emacs the symlink wasn't followed and it created a new
> abbrev_def file from somewhere, I don't know where.

This is strange.  I have my .abbrev_defs symlinked to elsewhere and it
works just fine.  I've been doing this for years, probably from emacs
v22 onwards (but that's just a guess).

To answer your original question, I use version control (e.g. src or
git) to manage that file along with other dotfiles.