pacer

1. One who paces.

2. In harness racing, a horse with a gait in which the front and back legs on one side take a step together alternating with the legs on the other side; as opposed to a trotter.

   a horse trained to a special gait in which both feet on one side leave the ground together

3. A pacemaker (one who sets the pace in a race).

4. A timer in an electric toothbrush that indicates how long the user should spend brushing in each part of the mouth.

5. (Australia)A mechanical pencil.

6. (archaic)A horse whose natural gait is a pace (where the legs of the same side are lifted together).

regular