The Wheel of the Year is divided into 8 seasons, in which are Pagan or Wiccan Sabbats. They call it the "Wheel" because of the seasons turn over and over again every year just like a wheel. These seasons are marked by 8 spokes in which we call the great Sabbats.
From the time of antiquity, no matter where in the world, the human race has always celebrated a type of ever-turning wheel of time marking the change in the seasons and times of harvests. Today's Pagans celebrate with the eight festivals that mark the important points in the cycles of Nature. These points are the two solstices and the two equinoxes. Pagans also have four cross-quarter sabbat days dividing the time between them. These cross quarters accentuate landmarks of times of farming, planting, gardening and all that is agricultural.
These sabbats are festivals and common across many Pagan traditions, including the Druid, Witch, Wiccan, Celtic, Norse (Asatru) and other Pagan spiritualist paths. The eight sabbats are: Yule, Imbolc, Ostara, Beltane, Litha, Lammas, Mebane and Samhain.