Mo'ed deals with holy days.
Excerpt from Stained Glass Quarterly article dated Fall 1989
Mo'ed (appointed seasons) deals with festivals, feasts and holy days. The most important holy day is Shabbat. According to the Talmudic sages, Shabbat is equal in importance to all the precepts in the Torah. "Shabbat stands at the boundary between the moral and the religious signification of the Torah. In the law of Shabbat is thus to be found the quintessence of Judaism." Religiously, Shabbat is a symbol of creation and the end of creation.
The window of Mo'ed, on an abstract level, is expressive of the separation of light from darkness. This relates to creation as well as to the blessing over the flames of the Havdalah candle. God is praised for the distinctive qualities throughout creation, including praise for the distinction between light and darkness. Symbolic reinforcement of this theme is seen in the braided candle and candle holder, cup for wine and box for spices of the Havdalah set (used during the concluding ritual of Shabbat). As literal reinforcement of the creation theme, the Hebrew words from Genesis, "...and the heavens and the earth were finished." are written in the upper central area. The content of this window is symbolic of beginning and ending.