The 5 wiccan elements are fire, water, earth, air and spirit, they are invoked during wiccan rituals to summon a particular spirit required to achieve an intention.
The spirit wiccan element unites all the other 4 wiccan elements. Each element is either warm or cold, and this corresponds with a male or female gender.
Because each element shares one of its qualities with one other element, that leaves one element completely unrelated.
Although nothing is a central part of the Wiccan religion, the five elements certainly play an important part in it.