| pitch circle | |
| —n | |
| an imaginary circle passing through the teeth of a gearwheel, concentric with the gearwheel, and having a radius that would enable it to be in contact with a similar circle around a mating gearwheel | |
| a fool or simpleton; ninny. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |