Do this like you'd do it anywhere in moodle -
Locate your uploaded .flv file (in the course files directory or elsewhere) and copy its URL;
In the text area of your Glossary page, type a blank space; highlight this, and click the link icon in the text editor bar to create a link;
Paste the .flv file's URL into the URL field in the link window & click OK.
The .flv will now stream on your page, via the mediaplugin filter. Configuration of the media player (size &c.) can be adjusted by editing the file