All of the planets move around our Sun in the same direction and have their own cycle time depending on their distance from the Sun.
The natal or birth chart is a snapshot of the heavens at the moment of our birth. From that moment on, the planets continue on their rotational path around the Sun and this continual movement of the planets is referred to as transiting planets. All of the planets eventually return to their original location that it was in at the moment of our birth (natal chart placement) but the outer planets (Uranus, Neptune and Pluto) take a long time to complete this cycle.
Upon being at the same degree and sign that it was at the moment of birth, the planet has made its return. Each planet takes a different length of time. The inner planets move more quickly and the outer planets take a much longer time to return.
We do not live long enough to experience some of the outer planet's return.