Pitch -

• The angular position of an object about a given reference line (usually horizontal) perpendicular to the direction of the object's travel. For a horizontal linear carriage, the line of rotation is about a horizontal line perpendicular to the nominal direction of motion (linear axis). Pitch is not well defined for a vertical carriage.
• The angle that a screw's threads make with respect to a plane that is perpendicular to the axis of the screw.
• The linear (shortest) distance between nearest common-angle points on a screw thread. ( e.g., The nominal distance per revolution that a ballscrew or leadscrew moves a carriage)