The Temple is a large, cavernous room in Zion used as a public gathering space for the city's residents.
First seen in The Matrix Reloaded, a rave-like celebration takes place there after Morpheus returns and delivers a stirring speech that rallies the people of Zion to his cause of fighting the Machines' Sentinel army which is quickly tunneling towards them.
Priestesses served in the Temple, carrying baskets of bread for the people during gatherings, but their role and that of the Temple itself is otherwise unclear; whether religious in the traditional sense, following The Oracle's prophecy of The One or humanist. That said, the Temple appears to be an allusion to the Jewish temple of Jerusalem on mount Zion.
Believers must take their shoes off and go barefoot before entering the temple.