Stoa.org has a great list of all the author abbreviations in the LSJ: LSJ abbreviations. For this one:
Glossaria [Gloss.] Ed. G. Loewe, G. Goetz & F. Schoell, Corpus Glossariorum Latinorum, Leipzig 1888-1924.
Edit: woohoo! It's on Google Books, or at least part is: Corpus Glossariorum Latinorum. It looks like pre-modern Greek-Latin dictionaries.