(Written in conjunction with José Luis Diaz, who introduced the idea of using BibTeX to create glossaries, and in fact the main author of the package.)
Gloss is a package which allows the creation of glossaries using BibTEX. With this approach, the user writes a database of terms and definitions using a file format much like the bibliographic databases. Then he inserts in the document a command for selecting which entries he wants to appear in the glossary. Running BibTEX these entries are extracted from the database and collected in alphabetical order in a file, which is read and inserted in the appropiate point of the document, typesetting the desired glossary or glossaries.